37 Roman Emperor Caligula accepted the titles of the Principate, entitled to him by the Senate.
364 Roman Emperor Valentinian I appointed his brother Flavius Valens co-emperor.
845 Paris was sacked by Viking raiders, probably under Ragnar Lodbrok, who collected a huge ransom in exchange for leaving.
1515 St. Teresa of Ávila was born. Teresa was a mystic, a reformer of the Carmelite order, and author of spiritual literature. She was the first woman to be named a doctor of the Church.