On April 12:
467 Anthemius was elevated to Emperor of the Western Roman Empire.
1204 Constantinople fell to the Crusaders of the Fourth Crusade, temporarily ending the Byzantine Empire.
1557 Cuenca was founded in Ecuador.
1606 The Union Flag was adopted as the flag of Great Britain.
1633 The formal inquest of Galileo Galilei by the Inquisition began.
1776 American Revolution: With the Halifax Resolves, the North Carolina Provincial Congress authorised its Congressional delegation to vote for independence from Britain.
1820 Alexander Ypsilantis was declared leader of Filiki Eteria, a secret organization to overthrow Ottoman rule over Greece.
1864 American Civil War: The Fort Pillow massacre: Confederate forces killed most African American soldiers who surrendered at Fort Pillow, Tennessee.
1877 The United Kingdom annexed the Transvaal.
1913 HMS New Zealand began a tour of New Zealand.
1917 World War I: Canadian forces successfully complete the taking of Vimy Ridge from the Germans.
1919 Billy Vaughn, American musician and bandleader, was born (d. 1991).
1932 Tiny Tim, American musician, was born (d. 1996).
1934 The strongest surface wind gust in the world at 231 mph, was measured on the summit of Mount Washington, USA.
1939 Alan Ayckbourn, English writer, was born.
1942 Jacob Zuma, President of South Africa, was born.
1945 US President Franklin D. Roosevelt died while in office; vice-president Harry Truman was sworn in as the 33rd President.
1947 Tom Clancy, American author, was born.
1947 David Letterman, American talk show host, was born.
1949 Scott Turow, American writer, was born.
1950 David Cassidy, American singer and actor, was born.
1955 The polio vaccine, developed by Dr Jonas Salk, was declared safe and effective.
1963 The Soviet nuclear powered submarine K-33 collided with the Finnish merchant vessel M/S Finnclipper in the Danish straits.
1968 Nerve gas accident at Skull Valley, Utah.
1978 Guy Berryman, British musician (Coldplay), was born.
1980 Brian McFadden, Irish Singer (Westlife) was born.
1980 Samuel Doe took control of Liberia in a coup d’état, ending over 130 years of national democratic presidential succession.
1990 Jim Gary’s Twentieth Century Dinosaurs exhibition opened at the Smithsonian Institution National Museum of Natural History in Washington, D.C.
1992 The Euro Disney Resort officially opened with its theme park Euro Disneyland.
1998 An earthquake in Slovenia, measuring 5.6 on the Richter scale occured near the town of Bovec.
1999 US President Bill Clinton was cited for contempt of court for giving “intentionally false statements” in a sexual harassment civil lawsuit.
2002 Pedro Carmona became interim President of Venezuela during the military coup against Hugo Chávez.
2002 – A female suicide bomber detonated at the entrance to Jerusalem’s Mahane Yehuda open-air market, killing 7 and wounding 104.
2007 A suicide bomber penetrated the Green Zone and detonated in a cafeteria within a parliament building, killing Iraqi MP Mohammed Awad and wounding more than twenty other people.
2010 – A train derailed near Merano, Italy, after running into a landslide, causing nine deaths and injuring 28 people.
Sourced from NZ History Online & Wikipedia