April 26th in stamps Delacroix, von Hindenburg, Count Basie, Lucille Ball, Bjørnstjerne Bjørnson

Here are some events that happened on April 26th. It could be an event or a person that died or was born on that day

1798 Born: Eugène Delacroix, French painter and lithographer (d. 1863)

Ferdinand Victor Eugène Delacroix (26 April 1798 – 13 August 1863) was a French Romantic artist regarded from the outset of his career as the leader of the French Romantic school.

As a painter and muralist, Delacroix's use of expressive brushstrokes and his study of the optical effects of colour profoundly shaped the work of the Impressionists, while his passion for the exotic inspired the artists of the Symbolist movement. A fine lithographer, Delacroix illustrated various works of William Shakespeare, the Scottish author Walter Scott and the German author Johann Wolfgang von Goethe.

In contrast to the Neoclassical perfectionism of his chief rival Ingres, Delacroix took for his inspiration the art of Rubens and painters of the Venetian Renaissance, with an attendant emphasis on colour and movement rather than clarity of outline and carefully modelled form. Dramatic and romantic content characterized the central themes of his maturity, and led him not to the classical models of Greek and Roman art, but to travel in North Africa, in search of the exotic. Friend and spiritual heir to Théodore Géricault, Delacroix was also inspired by Lord Byron, with whom he shared a strong identification with the "forces of the sublime", of nature in often violent action.

However, Delacroix was given to neither sentimentality nor bombast, and his Romanticism was that of an individualist. In the words of Baudelaire, "Delacroix was passionately in love with passion, but coldly determined to express passion as clearly as possible." Together with Ingres, Delacroix is considered one of the last old Masters of painting, and one of the few who was ever photographed.

Stamps from France depicting Delacroix's paintings or stamps depicting liberty based on Delacroix's painting Liberty Leading the People

1910 Died: Bjørnstjerne Bjørnson, Norwegian-French author and playwright, Nobel Prize laureate (b. 1832)

Bjørnstjerne Martinius Bjørnson (8 December 1832 – 26 April 1910) was a Norwegian writer who received the 1903 Nobel Prize in Literature "as a tribute to his noble, magnificent and versatile poetry, which has always been distinguished by both the freshness of its inspiration and the rare purity of its spirit", becoming the first Norwegian Nobel laureate. 

He was a prolific polemicist and extremely influential in Norwegian public life and Scandinavian cultural debate. Bjørnson is considered to be one of The Four Greats (De Fire Store) among Norwegian writers, the others being Henrik Ibsen, Jonas Lie, and Alexander Kielland. Bjørnson is also celebrated for his lyrics to the Norwegian National Anthem, "Ja, vi elsker dette landet". Composer Fredrikke Waaler based a composition for voice and piano (Spinnersken) on text by Bjørnson.

Norwegian stamps depicting Bjørnstjerne Bjørnson

1925 – Paul von Hindenburg defeats Wilhelm Marx in the second round of the German presidential election to become the first directly elected head of state of the Weimar Republic.

Paul Ludwig Hans Anton von Beneckendorff und von Hindenburg, known simply as Paul von Hindenburg (2 October 1847 – 2 August 1934), was a German general and statesman who commanded the Imperial German Army during World War I and later became President of Germany, serving from 1925 until his death in 1934, during the Weimar Republic. He played a key role in the Nazi Machtergreifung in January 1933 when, under pressure from advisers, he appointed Adolf Hitler chancellor of a "Government of National Concentration", even though the Nazis were a minority in both the cabinet and the Reichstag.

Born to a family of minor Prussian nobility, Hindenburg joined the Prussian army in 1866 where he thereafter saw combat during the Austro-Prussian War and the Franco-Prussian conflict. He retired with the rank of General of the Infantry in 1911, but was recalled to military service at the age of 66 following the outbreak of World War I in July 1914. On August 1914, he received nationwide attention as the victor of the Battle of Tannenberg. Upon later being named Chief of the General Staff in 1916, his popularity among the German public exponentially increased to the point of giving rise to an enormous personality cult. As Kaiser Wilhelm II increasingly delegated his power as Supreme Warlord to the Army High Command, Hindenburg and his deputy, General Erich Ludendorff, ultimately established a military dictatorship that controlled Germany for the rest of the war.

Hindenburg retired again in 1919, but returned to public life in 1925 to be elected the second President of Germany. In 1932, he was persuaded to run for re-election even though he was 84 years old and in poor health, because he was considered the only candidate who could defeat Hitler. Hindenburg was re-elected in a runoff. He was opposed to Hitler and was a major player in the increasing political instability in the Weimar Republic that ended with Hitler's rise to power. He dissolved the Reichstag twice in 1932 and finally agreed to appoint Hitler Chancellor of Germany in January 1933. Hindenburg did this to satisfy Hitler's demands that he should play a part in the Weimar government, for Hitler was the leader of the Nazi party, which had won a plurality in the November 1932 elections (no party achieved a majority). In February he approved the Reichstag Fire Decree, which suspended various civil liberties, and in March he signed the Enabling Act of 1933, which gave Hitler's regime arbitrary powers. Hindenburg died the following year, after which Hitler declared himself Führer und Reichskanzler, or Supreme Leader and Chancellor, which superseded both the President and Chancellor.

Mourning issue.. See also Mourning stamps with black perforation

100 pfenning stamp and with overprints used in Luxembourg and Lorraine

1984 Died: Count Basie, American pianist, composer, and bandleader (b. 1904)

William James "Count" Basie (August 21, 1904 – April 26, 1984) was an American jazz pianist, organist, bandleader, and composer. In 1935, Basie formed his own jazz orchestra, the Count Basie Orchestra, and in 1936 took them to Chicago for a long engagement and their first recording. He led the group for almost 50 years, creating innovations like the use of two "split" tenor saxophones, emphasizing the rhythm section, riffing with a big band, using arrangers to broaden their sound, and others. Many musicians came to prominence under his direction, including the tenor saxophonists Lester Young and Herschel Evans, the guitarist Freddie Green, trumpeters Buck Clayton and Harry "Sweets" Edison, plunger trombonist Al Grey, and singers Jimmy Rushing, Helen Humes, Thelma Carpenter, and Joe Williams.

US stamps depicting Count Basie

1989 Died: Lucille Ball, American model, actress, comedian, and producer (b. 1911)

Lucille Désirée Ball (August 6, 1911 – April 26, 1989) was an American actress, comedian, model, studio executive and producer. As one of Hollywood’s greatest icons, and arguably the most iconic female entertainer of all time, she was the star and producer of sitcoms I Love Lucy, The Lucy Show, Here's Lucy, as well as comedy television specials aired under the title The Lucy-Desi Comedy Hour. She is also the first female head of a major Hollywood studio, Desilu Productions, which she also owned.

Ball's career began in 1929 when she landed work as a model. Shortly thereafter, she began her performing career on Broadway using the stage name Diane (or Dianne) Belmont. She later appeared in several minor film roles in the 1930s and 1940s as a contract player for RKO Radio Pictures, being cast as a chorus girl or in similar roles. During this time, she met Cuban bandleader Desi Arnaz, and the two eloped in November 1940. In the 1950s, Ball ventured into television. In 1951, she and Arnaz created the sitcom I Love Lucy, a series that became one of the most beloved programs in television history. The same year, Ball gave birth to their first child, Lucie Arnaz, followed by Desi Arnaz Jr. in 1953. Ball and Arnaz divorced in May 1960, and she married comedian Gary Morton in 1961.

Following the end of I Love Lucy, Ball produced and starred in the Broadway musical Wildcat from 1960 to 1961. The show received lukewarm reviews and had to be closed when Ball became ill for several weeks. After Wildcat, Ball reunited with I Love Lucy co-star Vivian Vance for The Lucy Show, which Vance left in 1965. The show continued, with Ball's longtime friend and series regular Gale Gordon, until 1968. Ball immediately began appearing in a new series, Here's Lucy, with Gordon, frequent show guest Mary Jane Croft, and Lucie and Desi Jr.; this program ran until 1974.

In 1962, Ball became the first woman to run a major television studio, Desilu Productions, which produced many popular television series, including Mission: Impossible and Star Trek. Ball did not retire from acting completely, and in 1985, she took on a dramatic role in the television film Stone Pillow. The next year she starred in Life with Lucy, which was, unlike her other sitcoms, not well-received; the show was cancelled after three months. She appeared in film and television roles for the rest of her career until her death in April 1989 from an abdominal aortic aneurysm at the age of 77.

Ball was nominated for 13 Primetime Emmy Awards, winning four times. In 1960, she received two stars for her work in film and television on the Hollywood Walk of Fame. In 1977, Ball was among the first recipients of the Women in Film Crystal Award. She was also the recipient of the Golden Globe Cecil B. DeMille Award in 1979, was inducted into the Television Hall of Fame in 1984, received the Lifetime Achievement Award from the Kennedy Center Honors in 1986, and the Governors Award from the Academy of Television Arts & Sciences in 1989.

US stamps depicting Lucille Ball

April 23rd in stamps Maarten Tromp, Shakespeare, Max Planck

Here are some events that happened on April 23rd. It could be an event or a person that died or was born on that day

1598 Born: Maarten Tromp, Dutch admiral (d. 1653)

Maarten Harpertszoon Tromp (also written as Maerten Tromp; 23 April 1598 – 10 August 1653) was a Dutch army general and admiral in the Dutch navy.

In 1637, Tromp was promoted from captain to Lieutenant-Admiral of Holland and West Frisia in 1637, following the dismissal of Lieutenant-Admiral Philips van Dorp, Vice-Admiral Jasper Liefhebber, and other flag officers due to incompetence. Although formally ranking under the Admiral-General Frederick Henry of Orange, he was the de facto supreme commander of the Dutch fleet, as the stadtholders never fought at sea. Tromp was mostly occupied with blockading the privateer port of Dunkirk. Both Tromp and Witte de With, who was named as Vice-Admiral, had been born in Den Briel and served as flag captains of Piet Heyn.

In 1639, during the Dutch struggle for independence from Spain, Tromp defeated a large Spanish fleet bound for Flanders at the Battle of the Downs, marking the end of Spanish naval power. In a preliminary battle, the Action of 18 September 1639, Tromp was the first fleet commander known for the deliberate use of line of battle tactics. His flagship in this period was the Aemilia.

In 1643 the subject was the center of a parliamentary investigation of naval intrigue with the Queen of England and the Prince of Orange who had allegedly instructed the Vice-Admiral to allow passage of two frigates purchased by English royalists in Dunkirk.

In the First Anglo-Dutch War of 1652 to 1653, Tromp commanded the Dutch fleet in the battles of Dover, Dungeness, Portland, the Gabbard and Scheveningen. In the latter, he was killed by a sharpshooter in the rigging of William Penn's ship. His acting flag captain, Egbert Bartholomeusz Kortenaer, on the Brederode kept up fleet morale by not lowering Tromp's standard, pretending Tromp was still alive.

Tromp's death was a severe blow to the Dutch navy but also to the Orangists, who sought the defeat of the Commonwealth of England and the restoration of the Stuart monarchy. Republican influence strengthened after Scheveningen, which led to peace negotiations with the Commonwealth, culminating in the Treaty of Westminster.

During his career, his main rival was Vice-Admiral Witte de With, who also served the Admiralty of Rotterdam (de Maze) from 1637. De With temporarily replaced him as supreme commander for the Battle of Kentish Knock. Tromp's successor was Lieutenant-Admiral Jacob van Wassenaer Obdam.

Dutch stamps depicting Maarten Tromp

1616 Died: William Shakespeare, English playwright and poet (b. 1564)

William Shakespeare (bapt. 26 April 1564 – 23 April 1616) was an English playwright, poet, and actor, widely regarded as the greatest writer in the English language and the world's greatest dramatist. He is often called England's national poet and the "Bard of Avon" (or simply "the Bard"). His extant works, including collaborations, consist of some 39 plays, 154 sonnets, three long narrative poems, and a few other verses, some of uncertain authorship. His plays have been translated into every major living language and are performed more often than those of any other playwright. They also continue to be studied and reinterpreted.

Shakespeare was born and raised in Stratford-upon-Avon, Warwickshire. At the age of 18, he married Anne Hathaway, with whom he had three children: Susanna and twins Hamnet and Judith. Sometime between 1585 and 1592, he began a successful career in London as an actor, writer, and part-owner of a playing company called the Lord Chamberlain's Men, later known as the King's Men. At age 49 (around 1613), he appears to have retired to Stratford, where he died three years later. Few records of Shakespeare's private life survive; this has stimulated considerable speculation about such matters as his physical appearance, his sexuality, his religious beliefs, and whether the works attributed to him were written by others.

Shakespeare produced most of his known works between 1589 and 1613. His early plays were primarily comedies and histories and are regarded as some of the best work produced in these genres. He then wrote mainly tragedies until 1608, among them Hamlet, Romeo and Juliet, Othello, King Lear, and Macbeth, all considered to be among the finest works in the English language. In the last phase of his life, he wrote tragicomedies (also known as romances) and collaborated with other playwrights.

Many of Shakespeare's plays were published in editions of varying quality and accuracy in his lifetime. However, in 1623, two fellow actors and friends of Shakespeare's, John Heminges and Henry Condell, published a more definitive text known as the First Folio, a posthumous collected edition of Shakespeare's dramatic works that included all but two of his plays. The volume was prefaced with a poem by Ben Jonson, in which Jonson presciently hailed Shakespeare in a now-famous quote as "not of an age, but for all time".

Stamps from the US and Great Britain depicting Shakespeare or his works

1858 Born: Max Planck, German physicist and academic, Nobel Prize laureate (d. 1947)

Max Karl Ernst Ludwig Planck (23 April 1858 – 4 October 1947) was a German theoretical physicist whose discovery of energy quanta won him the Nobel Prize in Physics in 1918.

Planck made many contributions to theoretical physics, but his fame as a physicist rests primarily on his role as the originator of quantum theory, which revolutionized human understanding of atomic and subatomic processes. In 1948, the German scientific institution the Kaiser Wilhelm Society (of which Planck was twice president) was renamed the Max Planck Society (MPS). The MPS now includes 83 institutions representing a wide range of scientific directions.

Some stamps from Germany, East Germany and Berlin depicting Max Planck

April 21st in stamps John Muir, Max Weber, Mark Twain, Elizabeth II

Here are some events that happened on April 21st. It could be an event or a person that died or was born on that day

1838 Born: John Muir, Scottish-American environmentalist and author (d. 1914)

John Muir (April 21, 1838 – December 24, 1914) also known as "John of the Mountains" and "Father of the National Parks", was an influential Scottish-American naturalist, author, environmental philosopher, botanist, zoologist, glaciologist, and early advocate for the preservation of wilderness in the United States of America.

His letters, essays, and books describing his adventures in nature, especially in the Sierra Nevada, have been read by millions. His activism helped to preserve the Yosemite Valley and Sequoia National Park, and his example has served as an inspiration for the preservation of many other wilderness areas. The Sierra Club, which he co-founded, is a prominent American conservation organization. In his later life, Muir devoted most of his time to the preservation of the Western forests. As part of the campaign to make Yosemite a national park, Muir published two landmark articles on wilderness preservation in The Century Magazine, "The Treasures of the Yosemite" and "Features of the Proposed Yosemite National Park"; this helped support the push for U.S. Congress to pass a bill in 1890 establishing Yosemite National Park. The spiritual quality and enthusiasm toward nature expressed in his writings has inspired readers, including presidents and congressmen, to take action to help preserve large nature areas.

John Muir has been considered "an inspiration to both Scots and Americans". Muir's biographer, Steven J. Holmes, believes that Muir has become "one of the patron saints of twentieth-century American environmental activity," both political and recreational. As a result, his writings are commonly discussed in books and journals, and he has often been quoted by nature photographers such as Ansel Adams. "Muir has profoundly shaped the very categories through which Americans understand and envision their relationships with the natural world," writes Holmes.

Muir was noted for being an ecological thinker, political spokesman, and religious prophet, whose writings became a personal guide into nature for many people, making his name "almost ubiquitous" in the modern environmental consciousness. According to author William Anderson, Muir exemplified "the archetype of our oneness with the earth", while biographer Donald Worster says he believed his mission was "saving the American soul from total surrender to materialism." On April 21, 2013, the first John Muir Day was celebrated in Scotland, which marked the 175th anniversary of his birth, paying homage to the conservationist.

US stamps depicting John Muir,

1864 Born: Max Weber, German economist and sociologist (d. 1920)

Maximilian Karl Emil Weber (21 April 1864 – 14 June 1920) was a German sociologist, philosopher, jurist, and political economist, who is regarded today as one of the most important theorists on the development of modern Western society. As his ideas would profoundly influence social theory and social research, Weber is often cited as among the four founders of sociology, alongside W. E. B. Du Bois, Émile Durkheim, and Karl Marx.

Unlike Durkheim, Weber did not believe in monocausal explanations, proposing instead that for any outcome there can be multiple causes. As such, he would be a key proponent of methodological anti-positivism, arguing for the study of social action through interpretive (rather than purely empiricist) methods, based on understanding the purpose and meanings that individuals attach to their own actions. Weber's main intellectual concern was in understanding the processes of rationalisation, secularisation, and "disenchantment", which he took to be the result of a new way of thinking about the world, associating such processes with the rise of capitalism and modernity. 

Weber is best known for his thesis of combining economic sociology and the sociology of religion, emphasising the importance of cultural influences embedded in religion as a means for understanding the genesis of capitalism (contrasting Marx's historical materialism). Weber would first elaborate his theory in his seminal work, The Protestant Ethic and the Spirit of Capitalism (1905), in which he attributes ascetic Protestantism as one of the major "elective affinities" involved in the rise of market-driven capitalism and the rational-legal nation-state in the Western world. Arguing the boosting of capitalism as a basic tenet of Protestantism, Weber would suggest that the spirit of capitalism is inherent to Protestant religious values. Protestant Ethic would form the earliest part in Weber's broader investigations into world religion, as he would go on to examine the religions of China and India, as well as ancient Judaism, with particular regard to their differing economic consequences and conditions of social stratification.

Through another major work, "Politics as a Vocation", Weber would define "the state" as an entity that successfully claims a "monopoly of the legitimate use of physical force within a given territory." He would also be the first to categorise social authority into distinct forms: charismatic, traditional, and rational-legal. Among these categories, Weber's analysis of bureaucracy would emphasize that modern state institutions are increasingly based on the latter (rational-legal authority).

Weber also made a variety of other contributions in economic history, theory, and methodology. His analysis of modernity and rationalisation would significantly influence the critical theory associated with the Frankfurt School. After the First World War, he was among the founders of the liberal German Democratic Party. He also ran unsuccessfully for a seat in parliament and served as advisor to the committee that drafted the ill-fated democratic Weimar Constitution of 1919. After contracting Spanish flu, he died of pneumonia in 1920, aged 56.

1910 Died: Mark Twain, American novelist, humorist, and critic (b. 1835)

Samuel Langhorne Clemens (November 30, 1835 – April 21, 1910), known by his pen name Mark Twain, was an American writer, humorist, entrepreneur, publisher, and lecturer. He was lauded as the "greatest humorist the United States has produced," and William Faulkner called him "the father of American literature". His novels include The Adventures of Tom Sawyer (1876) and its sequel, the Adventures of Huckleberry Finn (1884), the latter often called "The Great American Novel".

Twain was raised in Hannibal, Missouri, which later provided the setting for Tom Sawyer and Huckleberry Finn. He served an apprenticeship with a printer and then worked as a typesetter, contributing articles to the newspaper of his older brother Orion Clemens. He later became a riverboat pilot on the Mississippi River before heading west to join Orion in Nevada. He referred humorously to his lack of success at mining, turning to journalism for the Virginia City Territorial Enterprise. His humorous story, "The Celebrated Jumping Frog of Calaveras County", was published in 1865, based on a story that he heard at Angels Hotel in Angels Camp, California, where he had spent some time as a miner. The short story brought international attention and was even translated into French. His wit and satire, in prose and in speech, earned praise from critics and peers, and he was a friend to presidents, artists, industrialists, and European royalty.

Twain earned a great deal of money from his writings and lectures, but he invested in ventures that lost most of it—such as the Paige Compositor, a mechanical typesetter that failed because of its complexity and imprecision. He filed for bankruptcy in the wake of these financial setbacks, but in time overcame his financial troubles with the help of Henry Huttleston Rogers. He eventually paid all his creditors in full, even though his bankruptcy relieved him of having to do so. Twain was born shortly after an appearance of Halley's Comet, and he predicted that he would "go out with it" as well; he died the day after the comet made its closest approach to the Earth.

US stamps and sheet depicting Mark Twain

1926 Born: Elizabeth II, Queen of the United Kingdom and her other realms

Elizabeth II (Elizabeth Alexandra Mary Windsor; born 21 April 1926) is Queen of the United Kingdom and the other Commonwealth realms.

Elizabeth was born in London as the first child of the Duke and Duchess of York, later King George VI and Queen Elizabeth, and she was educated privately at home. Her father acceded to the throne on the abdication of his brother King Edward VIII in 1936, from which time she was the heir presumptive. She began to undertake public duties during the Second World War, serving in the Auxiliary Territorial Service. In 1947, she married Prince Philip, Duke of Edinburgh, a former prince of Greece and Denmark, with whom she has four children: Charles, Prince of Wales; Anne, Princess Royal; Prince Andrew, Duke of York; and Prince Edward, Earl of Wessex

Stamps from Great Britain and Guernsey depicting Elizabeth II

April 19th in stamps James Cook, Note on the Theory of Diffraction, Lord Byron, Treaty of London, Konrad Adenauer, José Echegaray

Here are some events that happened on April 19th. It could be an event or a person that died or was born on that day

1770 – Captain James Cook, still holding the rank of lieutenant, sights the eastern coast of what is now Australia.

Captain James Cook (7 November 1728 – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the Royal Navy. He made detailed maps of Newfoundland prior to making three voyages to the Pacific Ocean, during which he achieved the first recorded European contact with the eastern coastline of Australia and the Hawaiian Islands, and the first recorded circumnavigation of New Zealand.

Cook joined the British merchant navy as a teenager and joined the Royal Navy in 1755. He saw action in the Seven Years' War and subsequently surveyed and mapped much of the entrance to the Saint Lawrence River during the siege of Quebec, which brought him to the attention of the Admiralty and Royal Society. This acclaim came at a crucial moment in his career and the direction of British overseas exploration, and led to his commission in 1766 as commander of HM Bark Endeavour for the first of three Pacific voyages.

In these voyages, Cook sailed thousands of miles across largely uncharted areas of the globe. He mapped lands from New Zealand to Hawaii in the Pacific Ocean in greater detail and on a scale not previously charted by Western explorers. He surveyed and named features, and recorded islands and coastlines on European maps for the first time. He displayed a combination of seamanship, superior surveying and cartographic skills, physical courage, and an ability to lead men in adverse conditions.

Cook was attacked and killed in 1779 during his third exploratory voyage in the Pacific while attempting to kidnap the Island of Hawaii's monarch, Kalaniʻōpuʻu, in order to reclaim a cutter stolen from one of his ships. He left a legacy of scientific and geographical knowledge that influenced his successors well into the 20th century, and numerous memorials worldwide have been dedicated to him.

Stamps from Australia, Cook Islands and the United States depicting James Cook

1818 – French physicist Augustin Fresnel signs his preliminary "Note on the Theory of Diffraction" (deposited on the following day). The document ends with what we now call the Fresnel integrals.

Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton's corpuscular theory, from the late 1830s  until the end of the 19th century. He is perhaps better known for inventing the catadioptric (reflective/refractive) Fresnel lens and for pioneering the use of "stepped" lenses to extend the visibility of lighthouses, saving countless lives at sea. The simpler dioptric (purely refractive) stepped lens, first proposed by Count Buffon  and independently reinvented by Fresnel, is used in screen magnifiers and in condenser lenses for overhead projectors.

By expressing Huygens's principle of secondary waves and Young's principle of interference in quantitative terms, and supposing that simple colors consist of sinusoidal waves, Fresnel gave the first satisfactory explanation of diffraction by straight edges, including the first satisfactory wave-based explanation of rectilinear propagation. Part of his argument was a proof that the addition of sinusoidal functions of the same frequency but different phases is analogous to the addition of forces with different directions. By further supposing that light waves are purely transverse, Fresnel explained the nature of polarization, the mechanism of chromatic polarization, and the transmission and reflection coefficients at the interface between two transparent isotropic media. Then, by generalizing the direction-speed-polarization relation for calcite, he accounted for the directions and polarizations of the refracted rays in doubly-refractive crystals of the biaxial class (those for which Huygens's secondary wavefronts are not axisymmetric). The period between the first publication of his pure-transverse-wave hypothesis, and the submission of his first correct solution to the biaxial problem, was less than a year.

Later, he coined the terms linear polarization, circular polarization, and elliptical polarization, explained how optical rotation could be understood as a difference in propagation speeds for the two directions of circular polarization, and (by allowing the reflection coefficient to be complex) accounted for the change in polarization due to total internal reflection, as exploited in the Fresnel rhomb. Defenders of the established corpuscular theory could not match his quantitative explanations of so many phenomena on so few assumptions.

Fresnel had a lifelong battle with tuberculosis, to which he succumbed at the age of 39. Although he did not become a public celebrity in his lifetime, he lived just long enough to receive due recognition from his peers, including (on his deathbed) the Rumford Medal of the Royal Society of London, and his name is ubiquitous in the modern terminology of optics and waves. After the wave theory of light was subsumed by Maxwell's electromagnetic theory in the 1860s, some attention was diverted from the magnitude of Fresnel's contribution. In the period between Fresnel's unification of physical optics and Maxwell's wider unification, a contemporary authority, Humphrey Lloyd, described Fresnel's transverse-wave theory as "the noblest fabric which has ever adorned the domain of physical science, Newton's system of the universe alone excepted."

French stamp depicting Augustin Fresnel

1824 Died: Lord Byron, English-Scottish poet and playwright (b. 1788)

George Gordon Byron, 6th Baron Byron (22 January 1788 – 19 April 1824), known simply as Lord Byron, was an English peer, who was a poet and politician. He was one of the leading figures of the Romantic movement and is regarded as one of the greatest English poets. He remains widely read and influential. Among his best-known works are the lengthy narrative poems Don Juan and Childe Harold's Pilgrimage; many of his shorter lyrics in Hebrew Melodies also became popular.

He travelled extensively across Europe, especially in Italy, where he lived for seven years in the cities of Venice, Ravenna, and Pisa. During his stay in Italy he frequently visited his friend and fellow poet Percy Bysshe Shelley. Later in life Byron joined the Greek War of Independence fighting the Ottoman Empire and died of disease leading a campaign during that war, for which Greeks revere him as a national hero. He died in 1824 at the age of 36 from a fever contracted after the First and Second Siege of Missolonghi.

His only marital child, Ada Lovelace, is regarded as a foundational figure in the field of computer programming based on her notes for Charles Babbage's Analytical Engine. Byron's extramarital children include Allegra Byron, who died in childhood, and possibly Elizabeth Medora Leigh, daughter of his half-sister Augusta Leigh.

Stamps from Greece, Hungary and Russia depicting Lord Byron

1832 Born: José Echegaray, Spanish engineer, mathematician, and playwright, Nobel Prize laureate (d. 1916)

José Echegaray y Eizaguirre (19 April 1832 – 14 September 1916) was a Spanish civil engineer, mathematician, statesman, and one of the leading Spanish dramatists of the last quarter of the 19th century. He was awarded the 1904 Nobel Prize for Literature "in recognition of the numerous and brilliant compositions which, in an individual and original manner, have revived the great traditions of the Spanish drama".

Theater had always been the love of José Echegaray's life. Although he had written earlier plays (La Hija natural and La Última Noche, both in 1867), he truly became a dramatist in 1874. His plays reflected his sense of duty, which had made him famous during his time in the governmental offices. Dilemmas centered on duty and morality are the motif of his plays. He replicated the achievements of his predecessors of the Spanish Golden Age, remaining a prolific playwright.

His most famous play is El gran Galeoto, a drama written in the grand nineteenth century manner of melodrama. It is about the poisonous effect that unfounded gossip has on a middle-aged man's happiness. Echegaray filled it with elaborate stage instructions that illuminate what we would now consider a hammy style of acting popular in the 19th century. Paramount Pictures filmed it as a silent with the title changed to The World and His Wife, and it was the basis for a later film The Great Galeoto. His most remarkable plays are O locura o santidad (Saint or Madman?, 1877); Mariana (1892); El estigma (1895); La duda, 1898; and El loco Dios (God, the fool, 1900).

Among his other famous plays are La esposa del vengador (1874) (The Avenger's Wife); En el puño de la espada (1875) (In the Sword's Handle); En el pilar y en la cruz (1878) (On the Stake and on the Cross); and Conflicto entre dos deberes (1882) (Conflict of Two Duties).

Along with the Provençal poet Frédéric Mistral, he was awarded the Nobel Prize for Literature in 1904, after having been nominated that year by a member of the Royal Spanish Academy, making him the first Spaniard to win the prize.

José Echegaray maintained constant activity until his death on 14 September 1916 in Madrid. His extensive work did not stop growing in his old age: in the final stage of his life he wrote 25 or 30 mathematical physics volumes. At the age of 83 he commented:

I cannot die, because if I am going to write my mathematical physics encyclopedia, I need at least 25 more years.

Swedish stamp depicting Echegaray 

1839 – The Treaty of London establishes Belgium as a kingdom and guarantees its neutrality.

The Treaty of London of 1839, also called the First Treaty of London, the Convention of 1839, the Treaty of Separation, the Quintuple Treaty of 1839, or the Treaty of the XXIV articles, was a treaty signed on 19 April 1839 between the Concert of Europe, the United Kingdom of the Netherlands and the Kingdom of Belgium. It was a direct follow-up to the 1831 Treaty of the XVIII Articles which the Netherlands had refused to sign, and the result of negotiations at the London Conference of 1838–1839.

Under the treaty, the European powers recognised and guaranteed the independence and neutrality of Belgium and established the full independence of the German-speaking part of Luxembourg. Article VII required Belgium to remain perpetually neutral, and by implication committed the signatory powers to guard that neutrality in the event of invasion.

Stamps from Belgium depicting Leopold I who was the first King of the Belgians

1967 Died: Konrad Adenauer, German politician, 1st Chancellor of Germany (b. 1876)

Konrad Hermann Joseph Adenauer (German: [ˈkɔnʁaːt ˈʔaːdənaʊɐ] (About this soundlisten); 5 January 1876 – 19 April 1967) was a German statesman who served as the first Chancellor of the Federal Republic of Germany (West Germany) from 1949 to 1963. He was co-founder and first leader of the Christian Democratic Union (CDU) (until 1966), a Christian Democratic party that under his leadership became one of the most influential parties in the country.

In the early years of the Federal Republic he switched focus from denazification to recovery and led his country from the ruins of World War II to becoming a productive and prosperous nation that forged close relations with France, the United Kingdom and the United States.  During his years in power, West Germany achieved democracy, stability, international respect and economic prosperity ("Wirtschaftswunder", German for "economic miracle").

Adenauer belied his age by his intense work habits and his uncanny political instinct. He displayed a strong dedication to a broad vision of market-based liberal democracy and anti-communism. A shrewd politician, Adenauer was deeply committed to a Western-oriented foreign policy and restoring the position of West Germany on the world stage. He worked to restore the West German economy from the destruction of World War II to a central position in Europe, presiding over the German Economic Miracle together with his Minister of Economics, Ludwig Erhard. He was a driving force in re-establishing national military forces (the Bundeswehr) in West Germany since 1955. Adenauer opposed rival East Germany and made his nation a member of NATO and a member of the Western Alliance.

Adenauer, who was Chancellor until age 87, was dubbed "Der Alte" ("the elder"). British politician and historian Roy Jenkins says he was "the oldest statesman ever to function in elected office." He remains the oldest head of government for a major country.

A devout Roman Catholic and member of the Catholic Centre Party, he was a leading politician in the Weimar Republic, serving as Mayor of Cologne (1917–1933) and as president of the Prussian State Council (1922–1933).

April 17th in stamps Trial of Martin Luther, Verrazzano, Benjamin Franklin, Ellis Island immigration center processes 11,747 people, Jean Baptiste Perrin

Here are some events that happened on April 17th. It could be an event or a person that died or was born on that day

1521 – Trial of Martin Luther over his teachings begins during the assembly of the Diet of Worms. Initially intimidated, he asks for time to reflect before answering and is given a stay of one day.

Martin Luther (10 November 1483 – 18 February 1546) was a German professor of theology, composer, priest, monk, and a seminal figure in the Protestant Reformation.

Luther was ordained to the priesthood in 1507. He came to reject several teachings and practices of the Roman Catholic Church; in particular, he disputed the view on indulgences. Luther proposed an academic discussion of the practice and efficacy of indulgences in his Ninety-five Theses of 1517. His refusal to renounce all of his writings at the demand of Pope Leo X in 1520 and the Holy Roman Emperor Charles V at the Diet of Worms in 1521 resulted in his excommunication by the pope and condemnation as an outlaw by the Holy Roman Emperor.

Luther taught that salvation and, consequently, eternal life are not earned by good deeds but are received only as the free gift of God's grace through the believer's faith in Jesus Christ as redeemer from sin. His theology challenged the authority and office of the Pope by teaching that the Bible is the only source of divinely revealed knowledge, and opposed sacerdotalism by considering all baptized Christians to be a holy priesthood. Those who identify with these, and all of Luther's wider teachings, are called Lutherans, though Luther insisted on Christian or Evangelical (German: evangelisch) as the only acceptable names for individuals who professed Christ.

His translation of the Bible into the German vernacular (instead of Latin) made it more accessible to the laity, an event that had a tremendous impact on both the church and German culture. It fostered the development of a standard version of the German language, added several principles to the art of translation, and influenced the writing of an English translation, the Tyndale Bible. His hymns influenced the development of singing in Protestant churches. His marriage to Katharina von Bora, a former nun, set a model for the practice of clerical marriage, allowing Protestant clergy to marry.

In two of his later works, Luther expressed antagonistic views towards Jews. His rhetoric was not directed at Jews alone, but also towards Roman Catholics, Anabaptists, and nontrinitarian Christians. Luther died in 1546 with Pope Leo X's excommunication still effective.


Stamps from several countries depicting Martin Luther

1524 – Giovanni da Verrazzano reaches New York harbor.

Giovanni da Verrazzano (1485–1528) was a Florentine explorer of North America, in the service of King Francis I of France.

He is renowned as the first European to explore the Atlantic coast of North America between Florida and New Brunswick in 1524, including New York Bay and Narragansett Bay.

Despite his discoveries, Verrazzano's reputation did not proliferate as much as other explorers of that era. For example, Verrazzano gave the European name Francesca to the new land that he had seen, in accordance with contemporary practices, after the French king in whose name he sailed. That and other names that he bestowed on features that he discovered have not survived. He had the misfortune of making major discoveries in the same three years (1519 to 1521) that the dramatic Conquest of Mexico and Ferdinand Magellan's circumnavigation of the world occurred. Magellan himself did not complete his voyage, but his publicist Antonio Pigafetta did so, and Spanish publicity outweighed the news of the French voyage.

In the 19th and the early 20th centuries, there was a great debate in the United States about the authenticity of the letters that he wrote to Francis I to describe the geography, flora, fauna, and native population of the east coast of North America. Others thought that they were authentic, almost universally the current opinion, particularly after the discovery of a letter signed by Francis I, which referred to Verrazzano's letter.

Verrazzano's reputation was particularly obscure in New York City, where the 1609 voyage of Henry Hudson on behalf of the Dutch Republic came to be regarded as the de facto start of European exploration of New York. It was only by a great effort in the 1950s and 1960s that Verrazzano's name and reputation were re-established as the European discoverer of the harbor, during an effort to name the newly built Narrows bridge after him.

Italian stamps depicting Giovanni da Verrazzano and the Verrazzano  bridge

1790 Died: Benjamin Franklin, American inventor, publisher, and politician, 6th President of Pennsylvania (b. 1706)

Benjamin Franklin (January 17, 1706 - April 17, 1790) was a British American polymath and one of the Founding Fathers of the United States. Franklin was a leading writer, printer, political philosopher, politician, Freemason, postmaster, scientist, inventor, humorist, civic activist, statesman, and diplomat. As a scientist, he was a major figure in the American Enlightenment and the history of physics for his discoveries and theories regarding electricity. As an inventor, he is known for the lightning rod, bifocals, and the Franklin stove, among other inventions. He founded many civic organizations, including the Library Company, Philadelphia's first fire department, and the University of Pennsylvania.

Franklin earned the title of "The First American" for his early and indefatigable campaigning for colonial unity, initially as an author and spokesman in London for several colonies. As the first United States ambassador to France, he exemplified the emerging American nation. Franklin was foundational in defining the American ethos as a marriage of the practical values of thrift, hard work, education, community spirit, self-governing institutions, and opposition to authoritarianism both political and religious, with the scientific and tolerant values of the Enlightenment. In the words of historian Henry Steele Commager, "In a Franklin could be merged the virtues of Puritanism without its defects, the illumination of the Enlightenment without its heat." To Walter Isaacson, this makes Franklin "the most accomplished American of his age and the most influential in inventing the type of society America would become."

Franklin became a successful newspaper editor and printer in Philadelphia, the leading city in the colonies, publishing the Pennsylvania Gazette at the age of 23. He became wealthy publishing this and Poor Richard's Almanack, which he authored under the pseudonym "Richard Saunders". After 1767, he was associated with the Pennsylvania Chronicle, a newspaper that was known for its revolutionary sentiments and criticisms of the policies of the British Parliament and the Crown.

He pioneered and was the first president of Academy and College of Philadelphia which opened in 1751 and later became the University of Pennsylvania. He organized and was the first secretary of the American Philosophical Society and was elected president in 1769. Franklin became a national hero in America as an agent for several colonies when he spearheaded an effort in London to have the Parliament of Great Britain repeal the unpopular Stamp Act. An accomplished diplomat, he was widely admired among the French as American minister to Paris and was a major figure in the development of positive Franco–American relations. His efforts proved vital for the American Revolution in securing shipments of crucial munitions from France.

He was promoted to deputy postmaster-general for the British colonies on August 10, 1753, having been Philadelphia postmaster for many years, and this enabled him to set up the first national communications network. During the revolution, he became the first United States postmaster general. He was active in community affairs and colonial and state politics, as well as national and international affairs. From 1785 to 1788, he served as governor of Pennsylvania. He initially owned and dealt in slaves but, by the late 1750s, he began arguing against slavery, became an abolitionist, and promoted education and the integration of blacks in American Society.

His life and legacy of scientific and political achievement, and his status as one of America's most influential Founding Fathers, have seen Franklin honored more than two centuries after his death on the fifty-cent piece, the $100 bill, warships, and the names of many towns, counties, educational institutions, and corporations, as well as numerous cultural references.

US stamps depicting Benjamin Franklin

1907 – The Ellis Island immigration center processes 11,747 people, more than on any other day.

Ellis Island is a federally owned island in New York Harbor that was the United States' busiest immigrant inspection station. From 1892 to 1924, approximately 12 million immigrants arriving at the Port of New York and New Jersey were processed there under federal law. Today, it is part of the Statue of Liberty National Monument, accessible to the public only by ferry. The north side of the island is the site of the main building, now a national museum of immigration. The south side of the island, including the Ellis Island Immigrant Hospital, is only open to the public through guided tours.

In the 19th century, Ellis Island was the site of Fort Gibson and later became a naval magazine. The first inspection station opened in 1892 and was destroyed by fire in 1897. The second station opened in 1900 and housed facilities for medical quarantines as well as processing immigrants. After 1924, Ellis Island was used primarily as a detention center for migrants. During both World War I and World War II its facilities were also used by the United States military to detain prisoners of war. Following the immigration station's closure, the buildings languished for several years until they partially reopened in 1976. The main building and adjacent structures were completely renovated in 1990.

The 27.5-acre (11.1 ha) island was greatly expanded by land reclamation between the late 1890s and the 1930s. Jurisdictional disputes between New Jersey and New York persisted until the 1998 U.S. Supreme Court ruling in New Jersey v. New York.

Stamp and a First Day Cover commemorating Ellis Island and immigrants

1942 Died: Jean Baptiste Perrin, French-American physicist and chemist, Nobel Prize laureate (b. 1870)

Jean Baptiste Perrin  (30 September 1870 – 17 April 1942) was a French physicist who, in his studies of the Brownian motion of minute particles suspended in liquids, verified Albert Einstein’s explanation of this phenomenon and thereby confirmed the atomic nature of matter (sedimentation equilibrium). For this achievement he was honoured with the Nobel Prize for Physics in 1926.

In 1895, Perrin showed that cathode rays were of negative electric charge in nature. He determined Avogadro's number (now known as the Avogadro constant) by several methods. He explained solar energy as due to the thermonuclear reactions of hydrogen.

After Albert Einstein published (1905) his theoretical explanation of Brownian motion in terms of atoms, Perrin did the experimental work to test and verify Einstein's predictions, thereby settling the century-long dispute about John Dalton's atomic theory. Carl Benedicks argued Perrin should receive the Nobel Prize in Physics; Perrin received the award in 1926 for this and other work on the discontinuous structure of matter, which put a definite end to the long struggle regarding the question of the physical reality of molecules.

Perrin was the author of a number of books and dissertations. Most notable of his publications were: "Rayons cathodiques et rayons X"; "Les Principes"; "Electrisation de contact"; "Réalité moléculaire"; "Matière et Lumière"; "Lumière et Reaction chimique".

Perrin was also the recipient of numerous prestigious awards including the Joule Prize of the Royal Society in 1896 and the La Caze Prize of the French Academy of Sciences. He was twice appointed a member of the Solvay Committee at Brussels in 1911 and in 1921. He also held memberships with the Royal Society of London and with the Academies of Sciences of Belgium, Sweden, Turin, Prague, Romania and China. He became a Commander of the Legion of Honour in 1926 and was made Commander of the Order of Léopold (Belgium).

In 1919, Perrin proposed that nuclear reactions can provide the source of energy in stars. He realized that the mass of a helium atom is less than that of four atoms of hydrogen, and that the mass-energy equivalence of Einstein implies that the nuclear fusion (4 H → He) could liberate sufficient energy to make stars shine for billions of years. A similar theory was first proposed by American chemist William Draper Harkins in 1915. It remained for Hans Bethe and Carl Friedrich von Weizsäcker to determine the detailed mechanism of stellar nucleosynthesis during the 1930s.

In 1927, he founded the Institut de Biologie Physico-Chimique together with chemist André Job and physiologist André Mayer. Funding was provided by Edmond James de Rothschild. In 1937, Perrin established the Palais de la Découverte, a science museum in Paris.

Perrin is considered the founding father of the National Centre for Scientific Research (Centre National de la Recherche Scientifique (CNRS)). Following a petition by Perrin signed by over 80 scientists, among them eight Nobel Prize laureates, the French education minister set up the Conseil Supérieur de la Recherche Scientifique (French National Research Council) in April 1933. In 1936, Perrin, now an undersecretary for research, founded the Service Central de la Recherche Scientifique (French Central Agency for Scientific Research). Both institutions were merged under the CNRS umbrella on October 19, 1939.

His notable students include Pierre Victor Auger. Jean Perrin was the father of Francis Perrin, also a physicist.

Stamp issued by Guyana depicting Jean Baptiste Perrin