Wikipedia:Selected anniversaries/April 21
April 21: Patriots' Day in Massachusetts and Maine (2008); Grounation Day in the Rastafari movement; First day of Ridván in the Bahá'í Faith; Tiradentes Day in Brazil.
- 753 BC – Romulus and Remus founded Rome, according to the calculations by Roman scholar Varro Reatinus.
- 1836 – Texan forces led by Sam Houston (pictured) defeated General Antonio López de Santa Anna and his Mexican troops in the Battle of San Jacinto near La Porte, the decisive battle in the Texas Revolution.
- 1894 – Norway formally adopted the Krag-Jørgensen, a repeating bolt action rifle designed by the Norwegians Ole Herman Johannes Krag and Erik Jørgensen, as the main firearm of its armed forces.
- 1918 – The German fighter pilot known as "The Red Baron", the most successful flying ace of World War I with 80 confirmed air combat victories, was shot down and killed near Vaux-sur-Somme in France.
- 1967 – Colonel Georgios Papadopoulos overthrew the government of Prime Minister Panagiotis Kanellopoulos in a coup d'état, establishing the Regime of the Colonels in Greece.
- 1970 – In response to a long-running dispute over wheat quotas, the Principality of Hutt River proclaimed their secession from Western Australia, but to this day has never been formally acknowledged by the Commonwealth of Australia or any other international entity.