31: Christians celebrate the first Easter, according to calendar maker Dionysius Exiguus

1436: Florence Cathedral (Cattedrale di Santa Maria del Fiore), started in 1296, is consecrated by Pope Eugene IV. Designed by Filippo Brunelleschi with support from Cosimo de’ Medici, it features the largest dome in the world at the time.

1807: British Parliament abolishes the slave trade throughout the British Empire; a penalty of £120 per slave is introduced for ship captains

1895: Italian troops invade Abyssinia (Ethiopia)

1960: First guided missile launched from a nuclear powered submarine (USS Halibut)

Source: Onthisday.com