On this day, May 26 …

2016: Donald Trump reaches the number of delegates necessary to clinch the Republican nomination for president.

Also on this day:

1647: Alse (Alice) Young is hanged in Hartford, Conn., in the first recorded execution of a "witch" in the American colonies.

Alse (Alice) Young is hanged in Hartford, Conn., in the first recorded execution of a "witch" in the American colonies. 1868: The impeachment trial of President Andrew Johnson ends with his acquittal.

The impeachment trial of President Andrew Johnson ends with his acquittal. 1897: "Dracula" by Bram Stoker is first published in London.

"Dracula" by Bram Stoker is first published in London. 1938: The House Un-American Activities Committee is established by Congress.

The House Un-American Activities Committee is established by Congress. 1940: Operation Dynamo, the evacuation of some 338,000 Allied troops from Dunkirk, France, begins during World War II.

Operation Dynamo, the evacuation of some 338,000 Allied troops from Dunkirk, France, begins during World War II. 1969: The Apollo 10 astronauts return to Earth after a successful eight-day dress rehearsal for the first manned moon landing.

The Apollo 10 astronauts return to Earth after a successful eight-day dress rehearsal for the first manned moon landing. 1972: President Richard M. Nixon and Soviet leader Leonid Brezhnev signed the Anti-Ballistic Missile Treaty in Moscow.

President Richard M. Nixon and Soviet leader Leonid Brezhnev signed the Anti-Ballistic Missile Treaty in Moscow. 1978: Resorts Casino Hotel, the first legal U.S. casino outside Nevada, opens in Atlantic City, N.J.

1998: The Supreme Court rules that Ellis Island is mainly in New Jersey and not in New York.

The Supreme Court rules that Ellis Island is mainly in New Jersey and not in New York. 2005: President George W. Bush hosts Palestinian Authority President Mahmoud Abbas at the White House.

President George W. Bush hosts Palestinian Authority President Mahmoud Abbas at the White House. 2009: President Barack Obama nominates federal appeals judge Sonia Sotomayor to the U.S. Supreme Court.