April 23

## Events 
### Up to 1900 
*215 BC &ndash; A temple is built on the Capitoline Hill dedicated to Venus Erycina to commemorate the Roman defeat at Lake Trasimene.
*711 &ndash; Dagobert III is crowned King of the Franks.
*1014 &ndash; Battle of Clontarf: Brian Boru defeats Viking invaders, but is killed in battle.
*1016 &ndash; Edmund Ironside becomes the Saxon king of England.
*1343 &ndash; Estonia: Saint George's Nigh Uprising.
*1348 &ndash; The founding of the Order of the Garter by King Edward III of England is announced on St George's Day.
*1521 &ndash; Battle of Villalar: King Charles I of Spain defeats the Comuneros.
*1533 &ndash; The Church of England annuls the marriage between Catherine of Aragon and Henry VIII of England.
*1597 &ndash; Shakespeare's *The Merry Wives of Windsor* is first performed, with Queen Elizabeth I of England in attendance.
*1660 &ndash; Treaty of Oliwa is established between Sweden and Poland.
*1661 &ndash; King Charles II of England, Scotland and Ireland is crowned in Westminster Abbey.
*1685 &ndash; King James II of England (James VII of Scotland) is crowned.
*1827 &ndash; William Rowan Hamilton presents his *Theory of systems of rays*.
*1867 &ndash; William Lincoln patents the zoetrope, a machine which shows animated pictures by mounting a strip of drawings in a wheel.
*1889 &ndash; Swedish Social Democratic Party is established.

### 1901 &ndash; 2000 
*1914 &ndash; The first baseball game at Wrigley Field, Chicago, takes place.
*1920 &ndash; The national council in Turkey denounces the government of Sultan Mehmed VI and announces a temporary constitution.
*1923 &ndash; Inauguration ceremonies take place of Gdynia as a temporary military port and fishers' shelter.
*1927 &ndash; Football: Cardiff City F.C. defeats Arsenal in the FA Cup final. With Cardiff City being in Wales, it is the only time a team based outside England has won this trophy.
*1929 &ndash; Turkey becomes the first country to celebrate Children's Day as a national holiday.
*1932 &ndash; The 153–year old De Adriaan Windmill in Haarlem, the Netherlands burns down.
*1935 &ndash; Polish Constitution of 1935 is adopted.
*1940 &ndash; Rhythm Night Club fire at a dance hall in Natchez, Mississippi kills 198 people.
*1941 &ndash; World War II: The Greek government and King George II of Greece evacuate Athens before the invading Wehrmacht.
*1942 &ndash; World War II: Baedeker Blitz – German bombers hit Exeter, Bath and York in retaliation for the British raid on Lübeck.
*1948 &ndash; 1948 Arab-Israeli War: Haifa, the major port of Israel, is captured from Palestinian forces.
*1954 &ndash; Hank Aaron hits his first major league home run.
*1956 &ndash; Elvis Presley makes his first appearance in Las Vegas, Nevada.
*1967 &ndash; A group of young radicals are expelled from the Nicaraguan Socialist Party (PSN). This group goes on to found the Socialist Workers Party (POS).
*1968 &ndash; The United Kingdom produces its first decimalised coins, a 5p and a 10p coin.
*1968 &ndash; Vietnam War: Student protesters at Columbia University in New York City take over administration buildings and shut down the university.
*1971 &ndash; Bangladesh Liberation War: Pakistan Army and the Razakars massacre around 3,000 Hindu emigrants in the Jathibhanga area of East Pakistan, present–day Bangladesh.
*1974 &ndash; A Pan American World Airways Boeing 707 crashes in Bali, Indonesia, killing 107.
*1979 &ndash; Fighting in London between the Anti-Nazi League and the Metropolitan Police's Special Patrol Group results in the death of protestor Blair Peach.
*1981 &ndash; Stefano Bontade, Mafia boss in Sicily, is murdered in Palermo, the opening shot in a mob war orchestrated by Salvatore Riina.
*1984 &ndash; The discovery of HIV is announced.
*1985 &ndash; Coca-Cola changes its 99 year old formula to the sweeter new Coke.  (It is doomed to failure and the company is later forced to reintroduce the original).
*1990 &ndash; Namibia becomes the 160th member of the United Nations and the 50th member of the Commonwealth of Nations.
*1990 &ndash; In a referendum in Karl Marx Stadt in then–East Germany, 76% of voters support changing their city's name back to Chemnitz.
*1993 &ndash; Eritreans vote overwhelmingly for independence from Ethiopia in a United Nations–monitored referendum.
*1994 &ndash; Physicists discover the top quark subatomic particle.
*1995 &ndash; Association of Autonomous Astronauts founded.
*1997 &ndash; Omaria massacre in Algeria; 42 villagers killed.

### From 2001 
*2003 &ndash; Beijing closes all schools for two weeks due to the SARS virus.
*2005 &ndash; The first YouTube video, called *Me at the Zoo*, is uploaded by the site's co–founder Jawed Karim.
*2006 &ndash; Hungary's Socialist Party wins the most votes in the country's parliamentary election, and can continue to govern with the Alliance of Free Democrats. This is the first re–election of a Hungarian government since the end of the Cold War.
*2009 &ndash; Gamma-ray burst GRB090423 is detected, coming from the most distant known astronomical object of any kind at the time.
*2013 &ndash; France legalizes same-sex marriage.
*2017 &ndash; French presidential election, 2017: Emmanuel Macron and Marine Le Pen advance to the second round, as the candidates of the main parties fail to get enough votes.
*2018 &ndash; A new prince, Louis, is born to Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge, with Princess Charlotte becoming the first British princess not to be overtaken by a younger brother in the line of succession to the throne.
*2018 &ndash; Serzh Sargsyan resigns as Prime minister of Armenia after only six days in office, following major protests in the capital, Yerevan. He had previously served ten years as President.
*2018 &ndash; A white van collided with numerous pedestrians killing ten people and injuring sixteen others at Yonge Street in Toronto. The suspect is arrested by police.
*2018 &ndash; Donald Trump receives his first state visit since becoming President of the United States, by Emmanuel Macron of France.

## Births 
### Up to 1800 
* 1141 &ndash; King Malcolm IV of Scotland (d. 1165)
* 1170 &ndash; Isabelle of Hainaut, Queen of France (d. 1190)
* 1185 &ndash; King Afonso II of Portugal (d. 1223)
* 1464 &ndash; Joan of France, Duchess of Berry (d. 1505)
* 1484 &ndash; Julius Caesar Scaliger, Italian philosopher (d. 1558)
* 1516 &ndash; Georg Fabricius, German poet, historian and archaeologist (d. 1571)
* 1522 &ndash; Catherine of Ricci, Italian saint (d. 1590)
* 1564 &ndash; William Shakespeare, English playwright (d. 1616)
* 1628 &ndash; Johann van Waveren Hudde, Dutch mathematician (d. 1704)
* 1676 &ndash; King Frederick I of Sweden (d. 1751)
* 1728 &ndash; Samuel Wallis, British naval officer and explorer (d. 1795)
* 1758 &ndash; Philip Gidley King, third Governor of New South Wales (d. 1808)
* 1775 &ndash; J. M. W. Turner, English painter (d. 1851)
* 1791 &ndash; James Buchanan, 15th President of the United States (d. 1868)
* 1792 &ndash; John Thomas Romney Robinson, Irish astronomer and physicist (d. 1882)
* 1794 &ndash; Wei Yuan, Chinese scholar (d. 1857)

### 1801 &ndash; 1900 
* 1804 &ndash; Marie Taglioni, Swedish ballerina (d. 1884)
* 1805 &ndash; Johann Karl Friedrich Rosenkranz, German philosopher (d. 1879)
* 1812 &ndash; Frederick Whitaker, Prime Minister of New Zealand (d. 1891)
* 1813 &ndash; Stephen A. Douglas, American politician (d. 1861)
* 1813 &ndash; Frédéric Ozanam, French literary scholar, lawyer and journalist (d. 1853)
* 1819 &ndash; Edward Stafford, Prime Minister of New Zealand (d. 1901)
* 1823 &ndash; Abd-ul-Mejid I, Ottoman Sultan (d. 1861)
* 1828 &ndash; Albert of Saxony (d. 1902)
* 1844 &ndash; Sanford Dole, American politician (d. 1926)
* 1845 &ndash; Pier Andrea Saccardo, Italian botanist (d. 1920)
* 1853 &ndash; Winthrop M. Crane, 40th Governor of Massachusetts (d. 1920)
* 1855 &ndash; Marco Fidel Suarez, President of Colombia (d. 1927)
* 1857 &ndash; Ruggero Leoncavallo, Italian composer (d. 1919)
* 1858 &ndash; Max Planck, German scientist (d. 1947)
* 1858 &ndash; Ethel Smyth, English composer, conductor, writer and Women's Rights activist (d. 1944) 
* 1867 &ndash; Johannes Andreas Grib Fibiger, Danish doctor, won the 1926 Nobel Prize in Physiology or Medicine (d. 1928)
* 1879 &ndash; Tom Berry, 14th Governor of South Dakota (d. 1951)
* 1880 &ndash; Mikhail Fokine, Russian choreographer and dancer (d. 1942)
* 1882 &ndash; Albert Coates, English composer and conductor (d. 1953)
* 1883 &ndash; Clara Pontoppidan, Danish actress (d. 1975)
* 1888 &ndash; Georges Vanier, 19th Governor General of Canada (d. 1967)
* 1889 &ndash; Karel Doorman, Dutch admiral (d. 1942)
* 1891 &ndash; Sergei Prokofiev, Russian composer (d. 1953)
* 1893 &ndash; Frank Borzage, American actor and director (d. 1952)
* 1894 &ndash; Cow Cow Davenport, American singer and pianist (d. 1955)
* 1895 &ndash; Ngaio Marsh, New Zealand writer (d. 1982)
* 1896 &ndash; Dmitry Dmitrievich Maksutov, Russian inventor (d. 1964)
* 1897 &ndash; Lester Pearson, Prime Minister of Canada (d. 1972)
* 1897 &ndash; Lucius D. Clay, American general (d. 1978)
* 1899 &ndash; Minoru Shirota, Japanese physician and inventor of Yakult (d. 1982)
* 1899 &ndash; Bertil Ohlin, Swedish economist (d. 1979)

### 1901  &ndash; 1950 
* 1901 &ndash; E.B. Ford, British ecological geneticist (d. 1988)
* 1902 &ndash; Halldór Laxness, Icelandic Nobel Prize–winning writer (d. 1998)
* 1907 &ndash; Lee Miller, American photographer (d. 1977)
* 1908 &ndash; Myron Waldman, American animator and director (d. 2006)
* 1910 &ndash; Simone Simon, French actress (d. 2005)
* 1911 &ndash; Ronald Neame, British movie producer (d. 2010)
* 1915 &ndash; Arnold Alexander Hall, British aeronautical engineer (d. 2000)
* 1917 &ndash; Dorian Leigh, American model (d. 2008)
* 1918 &ndash; Maurice Druon, French writer (d. 2009)
* 1919 &ndash; Oleg Penkovsky, Soviet double–agent (d. 1963)
* 1921 &ndash; Judy Agnew, wife of Spiro Agnew (d. 2012)
* 1922 &ndash; Marjorie Cameron, American writer, painter, actress and occultist (d. 1995)
* 1923 &ndash; Dolph Briscoe, Governor of Texas (d. 2010)
* 1924 &ndash; Bobby Rosengarden, American drummer and bandleader (d. 2007)
* 1924 &ndash; Margit Sandemo, Norwegian writer (d. 2018)
* 1926 &ndash; J. P. Donleavy, Irish–American writer (d. 2017)
* 1928 &ndash; Shirley Temple, American actress and political activist (d. 2014)
* 1929 &ndash; George Steiner, French–American literary critic, writer and philosopher
* 1936 &ndash; Roy Orbison, American singer (d. 1988)
* 1939 &ndash; Lee Majors, American actor
* 1939 &ndash; Stefano Bontade, Italian Mafia boss (d. 1981)
* 1940 &ndash; Michael Kadosh, Israeli footballer (d. 2014)
* 1941 &ndash; Paavo Lipponen, former Prime Minister of Finland
* 1941 &ndash; Jacqueline Boyer, French singer and actress
* 1941 &ndash; Arie den Hartog, Dutch road bicycle racer (d. 2018)
* 1942 &ndash; Sandra Dee, American actress (d. 2005)
* 1943 &ndash; Tony Esposito, Canadian ice hockey player
* 1943 &ndash; Frans Koppelaar, Dutch artist
* 1947 &ndash; Glenn Cornick, British musician (d. 2014)
* 1947 &ndash; Bernadette Devlin, Irish politician
* 1947 &ndash; Christer Pettersson, Swedish murder suspect (d. 2004)

### 1951 &ndash; 1975 
* 1952 &ndash; Narada Michael Walden, American singer-songwriter, drummer and producer
* 1953 &ndash; James Russo, American actor
* 1954 &ndash; Michael Moore, American movie maker
* 1955 &ndash; Judy Davis, Australian actress
* 1955 &ndash; Tony Miles, English chess player
* 1955 &ndash; Mike Smith, English television and radio presenter (d. 2014)
* 1957 &ndash; Jan Hooks, American actress (d. 2014)
* 1957 &ndash; Neville Brody, English graphic designer, typographer and art director
* 1958 &ndash; Hilmar Orn Hilmarsson, Icelandic composer
* 1958 &ndash; Magnus Andersson, Swedish footballer
* 1960 &ndash; Valerie Bertinelli, American actress
* 1960 &ndash; Steve Clark, English guitarist (Def Leppard) (d. 1991)
* 1960 &ndash; Claude Julien, Canadian ice hockey player and coach
* 1961 &ndash; Dirk Bach, German actor and television presenter (d. 2012)
* 1961 &ndash; George Lopez, American comedian, actor and talk show host
* 1962 &ndash; John Hannah, Scottish actor
* 1962 &ndash; Hillel Slovak, American musician (Red Hot Chili Peppers) (d. 1988)
* 1962 &ndash; Elaine Smith, British actress
* 1963 &ndash; Paul Belmondo, French actor and racing driver
* 1963 &ndash; Magnus Ver Magnusson, Icelandic powerlifter, four–times winner of World's Strongest Man title
* 1963 &ndash; Robby Naish, American windsurfer 
* 1964 &ndash; Gianandrea Noseda, Italian conductor
* 1966 &ndash; Lembit Oll, Estonian chess player (d. 1999)
* 1967 &ndash; Melina Kanakaredes, American actress
* 1968 &ndash; Princess Aisha bint al Hussein of Jordan
* 1968 &ndash; Princess Zein bint al Hussein of Jordan
* 1968 &ndash; Timothy McVeigh, American terrorist (d. 2001)
* 1969 &ndash; Yelena Shushunova, Russian gymnast
* 1972 &ndash; Patricia Manterola, Mexican singer, actress and fashion designer
* 1973 &ndash; Patrick Poulin, Canadian ice hockey player
* 1975 &ndash; Jón Thór Birgisson (Jónsi), Icelandic singer

### From 1976 
* 1976 &ndash; Brendan Cole, New Zealand dancer
* 1977 &ndash; Lee Young-Pyo, South Korean footballer
* 1977 &ndash; John Cena, American wrestler, rapper and actor
* 1979 &ndash; Barry Fratelli, Scottish musician (The Fratellis)
* 1979 &ndash; Lauri Ylönen, Finnish singer (The Rasmus)
* 1979 &ndash; Samppa Lajunen, Finnish skier
* 1979 &ndash; Barry Hawkins, English snooker player
* 1979 &ndash; Jaime King, American model and actress
* 1979 &ndash; Yana Gupta, Czech model, actress and author
* 1980 &ndash; Taio Cruz, English singer
* 1981 &ndash; Lady Gabriella Windsor, member of the extended British Royal Family
* 1982 &ndash; Andy Webster, Scottish footballer
* 1983 &ndash; Daniela Hantuchova, Slovakian tennis player
* 1983 &ndash; Jay Cutler, American football player
* 1983 &ndash; Aaron Hill, American actor
* 1984 &ndash; Alexandra Kosteniuk, Russian chess player
* 1984 &ndash; Ross Ford, Scottish rugby player
* 1984 &ndash; Fumihisa Yumoto, Japanese ski jumper
* 1985 &ndash; Tony Martin, German cyclist
* 1986 &ndash; Aleksei Rebko, Russian footballer
* 1987 &ndash; Emily Fox, American cup stacker and basketball player
* 1987 &ndash; Laura Mvula, English singer
* 1987 &ndash; Boaz Ma'uda, Israeli singer
* 1988 &ndash; Alistair Brownlee, English triathlete
* 1988 &ndash; Molly Burnett, American actress and singer
* 1988 &ndash; Steph Houghton, English footballer
* 1988 &ndash; Victor Anichebe, Nigerian footballer
* 1989 &ndash; Nicole Vaidisova, Czech tennis player
* 1990 &ndash; Dev Patel, British actor
* 1993 &ndash; Rina Chikano, Japanese singer (AKB48)
* 1994 &ndash; Patrick Olsen, Danish footballer
* 1995 &ndash; Gigi Hadid, American model
* 1997 &ndash; Alex Ferris, Canadian actor
* 2018 &ndash; Prince Louis of Cambridge

## Deaths 
### Up to 1900 
* 303 &ndash; Saint George, Christian martyr and patron Saint (date of birth unknown)
* 711 &ndash; King Childebert III of the Franks (b. 670)
* 725 &ndash; Wihtred, King of Kent
* 871 &ndash; Ethelred of Wessex, Saxon king
* 1014 &ndash; Brian Boru, High King of Ireland
* 1016 &ndash; Ethelred the Unready, Saxon king (b. 968)
* 1124 &ndash; Alexander I of Scotland (b. 1078)
* 1217 &ndash; Inge II of Norway (b. 1185)
* 1307 &ndash; Joan of Acre, daughter of Edward I of England (b. 1272)
* 1605 &ndash; Tsar Boris Godunov of Russia (b. c. 1550)
* 1616 &ndash; Garcilaso de la Vega, Peruvian historian and writer (b. 1539)
* 1616 &ndash; Miguel de Cervantes, Spanish writer (b. 1547)
* 1616 &ndash; William Shakespeare, English playwright (b. 1564)
* 1625 &ndash; Maurice, Prince of Orange (b. 1567)
* 1670 &ndash; Loreto Vittori, Italian singer (b. 1604)
* 1794 &ndash; Guillaume-Chretien de Lamoignon de Malesherbes, French statesman (b. 1721)
* 1827 &ndash; Georgios Karaiskakis, hero of the Greek War of Independence (b. 1780)
* 1850 &ndash; William Wordsworth, English poet (b. 1770)
* 1895 &ndash; Carl Ludwig, German physician (b. 1815)

### 1901 &ndash; 2000 
* 1905 &ndash; Gédéon Ouimet, 2nd Premier of Quebec (b. 1823)
* 1915 &ndash; Rupert Brooke, English poet (b. 1887)
* 1951 &ndash; Charles G. Dawes, Vice President of the United States (b. 1865)
* 1965 &ndash; George Adamski, Polish–American writer, teacher and ufologist (b. 1891)
* 1969 &ndash; Krzysztof Komeda, Polish jazz pianist and composer (b. 1931)
* 1975 &ndash; William Hartnell, English actor (b. 1908)
* 1981 &ndash; Josep Pla, Catalan journalist and writer (b. 1897)
* 1981 &ndash; Stefano Bontade, Italian Mafia boss (b. 1939)
* 1983 &ndash; Buster Crabbe, American singer and actor (b. 1908)
* 1984 &ndash; Red Garland, American jazz pianist (b. 1923)
* 1986 &ndash; Harold Arlen, American composer (b. 1905)
* 1986 &ndash; Otto Preminger, Austrian director (b. 1906)
* 1990 &ndash; Paulette Goddard, American actress (b. 1910)
* 1992 &ndash; Tanka Prasad Acharya, 27th Prime Minister of Nepal (b. 1912)
* 1992 &ndash; Satyajit Ray, Indian movie maker (b. 1921)
* 1993 &ndash; César Chávez, Mexican–American activist (b. 1927)
* 1995 &ndash; Douglas Lloyd Campbell, Canadian politician, 13th Premier of Manitoba (b. 1895)
* 1996 &ndash; P. L. Travers, Australian writer (b. 1899)
* 1996 &ndash; Mario Luigi Ciappi, Italian cardinal (b. 1909)
* 1997 &ndash; Hamani Diori, 1st President of Niger (b. 1916)
* 1998 &ndash; James Earl Ray, convicted assassin of Martin Luther King, Jr. (b. 1928)
* 1998 &ndash; Konstantinos Karamanlis, Greek politician (b. 1907)

### From 2001 
* 2003 &ndash; Fernand Fonssagrives, French photographer (b. 1910)
* 2005 &ndash; Joh Bjelke-Petersen, Australian politician, Premier of Queensland (b. 1911)
* 2007 &ndash; Boris Yeltsin, former President of Russia (b. 1931)
* 2007 &ndash; David Halberstam, American journalist and writer (b. 1934)
* 2011 &ndash; John Sullivan, British television writer (b. 1946)
* 2011 &ndash; Norio Ogha, Japanese businessman (b. 1930)
* 2012 &ndash; Tommy Marth, American musician (b. 1978)
* 2013 &ndash; Robert W. Edgar, American politician (b. 1943)
* 2014 &ndash; Mark Shand, British travel writer and conservationist, brother of Camilla, Duchess of Cornwall (b. 1951)
* 2014 &ndash; Michael Glawogger, Austrian movie director, screenwriter and cinematographer (b. 1959)
* 2014 &ndash; Connie Marrero, Cuban baseball player, oldest living Major League Baseball player (b. 1911)
* 2014 &ndash; Yozo Aoki, Japanese footballer (b. 1929)
* 2015 &ndash; Sixto Valencia Burgos, Mexican comic artist (b. 1934)
* 2015 &ndash; Sawyer Sweeten, American actor (b. 1995)
* 2015 &ndash; Aziz Asli, Iranian footballer (b. 1938)
* 2015 &ndash; Richard Corliss, American movie critic (b. 1944)
* 2015 &ndash; Francis Tsai, American comic book, movie and video game concept artist (b. 1967)
* 2015 &ndash; Pierre Claude Nolin, Canadian politician (b. 1950)
* 2016 &ndash; Banharn Silpa-archa, Prime Minister of Thailand (b. 1932)
* 2016 &ndash; Inge King, German–Australian sculptor (b. 1915)
* 2016 &ndash; Ron Brace, American football player (b. 1986)
* 2016 &ndash; Miguel Picazo, Spanish movie director (b. 1927)
* 2016 &ndash; Madeleine Sherwood, Canadian actress (b. 1922)
* 2017 &ndash; Isiaka Adeleke, Nigerian politician (b. 1955)
* 2017 &ndash; Jerry Adriani, Brazilian singer and actor (b. 1947)
* 2017 &ndash; Chris Bearde, Australian comedy writer and producer (b. 1936)
* 2017 &ndash; Kathleen Crowley, Australian actress (b. 1929)
* 2017 &ndash; Imre Földi, Hungarian weightlifter (b. 1938)
* 2017 &ndash; Ken Sears, American basketball player (b. 1933)
* 2017 &ndash; Leo Baxendale, British comics artist (b. 1930)
* 2017 &ndash; Chriet Titulaer, Dutch astronomer, television presenter and writer (b. 1943)
* 2017 &ndash; Michael Williams, Baron Williams of Baglan, British peer and diplomat (b. 1949)
* 2018 &ndash; Haddon Donald, New Zealand army lieutenant colonel and politician (b. 1917)
* 2018 &ndash; Bob Dorough, American jazz pianist, composer and singer-songwriter (b. 1923)
* 2018 &ndash; Béla Magyari, Hungarian air force colonel (b. 1949)
* 2018 &ndash; Jerrold Meinwald, American chemist (b. 1927)
* 2018 &ndash; Leland B. Yeager, American economist (b. 1924)
* 2019 &ndash; Henry W. Bloch, American businessman (b. 1922)
* 2019 &ndash; Matthew Buckland, South African businessman (b. 1974)
* 2019 &ndash; George Haigh, English footballer (b. 1915)
* 2019 &ndash; Jean, Grand Duke of Luxembourg (b. 1921)
* 2019 &ndash; Mark Medoff, American playwright and screenwriter (b. 1940)
* 2019 &ndash; Juan José Muñante, Peruvian footballer (b. 1948)
* 2019 &ndash; Terry Rawlings, British film editor (b. 1933)
* 2019 &ndash; Peter Skipper, English footballer (b. 1958)
* 2019 &ndash; David Winters, English choreographer (b. 1939)

## Observances 
* Saint George's Day – Patron Saint of many places, including England and Catalonia
* UN English language Day
* World Book Day
* National Sovereignty and Children's Day (Turkey)
* National Beer Day (Germany)
* Latest possible date for Good Friday, in relation to Easter

## References