1436 – Assassination of the Swedish rebel (later national hero) Engelbrekt Engelbrektsson
1626 – Dutch explorer Peter Minuit arrives in New Netherland (present day Manhattan Island) aboard the See Meeuw.
1675 – King Charles II of England orders the construction of the Royal Greenwich Observatory.
1776 – Rhode Island becomes the first American colony to renounce allegiance to King George III.
1886 – Haymarket affair: A bomb is thrown at policemen trying to break up a labor rally in Chicago, in support of workers striking for an eight-hour day and in reaction to the killing of several workers the previous day by the police. The bomb blast and ensuing gunfire resulted in the deaths of seven police officers and at least four civilians; scores of others were wounded.
1904 – The United States begins construction of the Panama Canal.
1919 – May Fourth Movement: Student demonstrations take place in Tiananmen Square in Beijing, China, protesting the Treaty of Versailles, which transferred Chinese territory to Japan.
1926 – The United Kingdom general strike begins.
1953 – Ernest Hemingway wins the Pulitzer Prize for The Old Man and the Sea.
1961 – American civil rights movement: The “Freedom Riders” begin a bus trip through the South.
1970 – Kent State shootings: The Ohio National Guard, sent to Kent State University after disturbances in the city of Kent the weekend before, opens fire killing four unarmed students and wounding nine others. The students were protesting the Cambodian Campaign of the United States and South Vietnam.
1982 – Twenty sailors are killed when the British Type 42 destroyer HMS Sheffield is hit by an Argentinian Exocet missile during the Falklands War.
1989 – Iran-Contra affair: Former White House aide Oliver North is convicted of three crimes and acquitted of nine other charges; the convictions are later overturned on appeal.
1998 – A federal judge in Sacramento, California, gives “Unabomber” Theodore Kaczynski four life sentences plus 30 years after Kaczynski accepts a plea agreement sparing him from the death penalty.
Births
1655 – Bartolomeo Cristofori, Italian instrument maker, invented the piano (d. 1731)
1796 – Horace Mann, American educator and politician (d. 1859)
1907 – Lincoln Kirstein, American soldier and playwright, co-founded the New York City Ballet (d. 1996)
1916 – Jane Jacobs, American-Canadian journalist, author, and activist (d. 2006)
1928 – Wolfgang von Trips, German race car driver (d. 1961)
1929 – Audrey Hepburn, British actress and humanitarian (d. 1993)
1958 – Keith Haring, American painter (d. 1990)
Deaths
1980 – Josip Broz Tito, President of Yugoslavia (b. 1892)
Edited from various sources including historyorb.com, the NYTimes.com Wikipedia and other internet searches