21 April History
- 753 BC - Traditional date of the foundation of Rome.
- 43 BC - Marcus Antonius is defeated by Octavian near Modena, Italy.
- 1526 - Mongol Emperor Babur annihilates the Indian Army of Ibrahim Lodi.
- 1649 - The Maryland Toleration Act is passed, allowing all people freedom of worship.
- 1689 - William III and Mary II are crowned joint king and queen of England, Scotland and Ireland.
- 1836 - General Sam Houston defeats Santa Anna at the Battle of San Jacinto. Texas wins independence from Mexico.
- 1862 - Congress establishes the U.S. Mint.
- 1865 - Abraham Lincoln's funeral train leaves Washington.
- 1898 - The Spanish-American War begins.
- 1910 - Mark Twain dies at the age of 75.
- 1916 - Bill Carlisle, the infamous 'last train robber,' robs a train in Hanna, Wyoming.
- 1914 - U.S. Marines occupy Vera Cruz, Mexico. They will stay six months.
- 1918 - German fighter ace Baron von Richthofen, "The Red Baron," is shot down and killed.
- 1943 - President Roosevelt announces that several Doolittle pilots have been executed by Japanese.
- 1960 - Brasilia becomes the capital of Brazil.
- 1961 - The French army revolts in Algeria.
- 1966 - Pfc. Milton Lee Olive is awarded the Medal of Honor, posthumously, for bravery during the Vietnam War.
- 1975 - The last South Vietnam president, Nguyen Van Thieu, resigns.
- 1995 - Federal authorities arrest Timothy McVeigh in connection with the Oklahoma City bombing.
21 April Birthdays
- 1782 - Friedrich Froebel, founder of kindergarten.
- 1816 - Charlotte Bronte, novelist (Jane Eyre).
- 1838 - John Muir, naturalist.
- 1849 - Oskar Hertwig, embryologist.
- 1864 - Max Weber, German sociologist and political economist.
- 1909 - Rollo May, psychologist.
- 1912 - Marcel Camus, French film director (Black Orpheus).
- 1923 - John Mortimor, British barrister and playwright (Rumpole of the Bailey).
- 1926 - Elizabeth II, queen of England.
- 1932 - Elaine May, comedy writer.