President Nguyen Van Thieu of South Vietnam is escorted by Vice President Spiro Agnew upon arrival at nearby Andrews Air Force base on April 4, 1973. On April 21, 1975, Nguyen Van Thieu resigned as president of South Vietnam after denouncing the United States as untrustworthy. UPI File Photo | License Photo

Visitors stop for a tour of the Alamo in San Antonio on February 9, 2015. On April 21, 1836, with the battle cry "Remember the Alamo!" Texas forces under Sam Houston defeated the army of Mexican Gen. Antonio Lopez de Santa Anna at San Jacinto, Texas, opening the path to Texas independence. File Photo by Bill Greenblatt/UPI | License Photo

Sen. John Ensign, R-Nev., addresses the delegates on the last day of the Republican National Convention in St. Paul, Minn., on September 4, 2008. On April 21, 2011 he resigned his U.S. Senate seat amid a budding ethics scandal. File Photo by Roger L. Wollenberg/UPI | License Photo

On April 21, 1918, Manfred von Richthofen, German World War I flying ace known as "The Red Baron," was killed by Allied fire over Vaux-sur-Somme, France. File Photo by C.J. von Duhren

April 21 (UPI) -- On this date in history:

In 1509, Henry VIII became king of England after his father, Henry VII, died.


In 1836, with the battle cry "Remember the Alamo!" Texas forces under Sam Houston defeated the army of Mexican Gen. Antonio Lopez de Santa Anna at San Jacinto, Texas, opening the path to Texas independence.

In 1913, California state Sen. Ernest S. Birdsall of Placer County stated in an interview with United Press that the citizens of California demanded the prohibition of "aliens ineligible for citizenship" from owning farm land. The California Alien Land Law of 1913 was aimed at discouraging immigration to the state.

In 1918, Manfred von Richthofen, German World War I flying ace known as "The Red Baron," was killed by Allied fire over Vaux-sur-Somme, France.

In 1954, U.S. Air Force planes began flying French troops to Indochina to reinforce Dien Bien Phu. The city later fell to communist Viet Minh forces.

In 1960, Brasilia was inaugurated as Brazil's capital, moving the seat of government from Rio de Janeiro.

In 1967, a Greek army coup in Athens sent King Constantine into exile in Italy.

In 1975, Nguyen Van Thieu resigned as president of South Vietnam after denouncing the United States as untrustworthy. His replacement, Tran Van Huong, prepared for peace talks with North Vietnam as communist forces advanced on Saigon.

In 1987, the bombing of a bus terminal in Colombo, Sri Lanka, killed 127 people and injured 288.

In 1992, gas explosions ripped through the historic center of Guadalajara, Mexico, killing more than 200 people and injuring hundreds of others.

In 2005, the U.S. Senate approved the nomination of John Negroponte to be the nation's first national intelligence director.

In 2008, the U.S. Food and Drug Administration announced a link had been found between contaminated drug thinners from China and 81 deaths in the United States.

In 2011, John Ensign, R-Nev., resigned his U.S. Senate seat amid a budding ethics scandal. Ensign admitted an affair with his former campaign treasurer earlier and had been under Republican pressure to step down.

In 2017, a Taliban attack on Camp Shaheen near Mazar-i-Sharif, Afghanistan, left more than 100 Afghan soldiers dead and dozens injured.

In 2018, Oakland Athletics lefty Sean Manaea threw the first no-hitter of the season in a 3-0 win against the Boston Red Sox.