Today:
312: Constantine the Great reportedly received his Vision of the Cross, which he believed led to his victory at the Battle of the Milvian Bridge.
1275: The traditional date for the founding of the city of Amsterdam is established, based on a document granting toll-free status to its residents.
1682: William Penn founded the city of Philadelphia in the Commonwealth of Pennsylvania.
1787: The first of the Federalist Papers, a series of essays arguing for the ratification of the United States Constitution, was published in a New York newspaper.
1838: Missouri Governor Lilburn W. Boggs issued Executive Order 44, commonly known as the “Extermination Order,” directing that Mormons be driven from the state.
1904: The first underground line of the New York City Subway system opened to the public.
1936: Wallis Simpson obtained a preliminary decree of divorce, paving the way for her to marry King Edward VIII of the United Kingdom, which led to his abdication.
1954: Benjamin O. Davis, Jr. became the first African-American general in the United States Air Force.
1961: NASA conducted the first test flight of the Saturn I rocket, a crucial step in the Apollo program to land humans on the Moon.
1991: Turkmenistan declared its independence from the Soviet Union following a national referendum.