31: The first Easter, according to calendar-maker Dionysius Exiguus

1436: Florence Cathedral, Cattedrale di Santa Maria del Fiore, consecrated by Pope Eugene IV, the largest dome in the world (then) by Filippo Brunelleschi with support from Cosimo de’ Medici (begun 1296)

1807: British Parliament abolishes the slave trade throughout the British Empire; penalty of £120 per slave 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