On This Day: May 15

Liu Bei, Chinese warlord, proclaims himself emperor of Shu Han, the successor of the Han dynasty.

Emperor Valentinian II is assassinated while advancing into Gaul against the Frankish usurper Arbogast. He is found hanging in his residence at Vienne.

King Authari marries Theodelinda, daughter of the Bavarian duke Garibald I. A Catholic, she has great influence among the Lombard nobility.

The three-year-old Constantine VII, the son of Emperor Leo VI the Wise, is crowned as co-emperor of the Byzantine Empire by Patriarch Euthymius I at Constantinople.

Pope Innocent IV issues the papal bull ad extirpanda, which authorizes, but also limits, the torture of heretics in the Medieval Inquisition.

Insurgent peasants led by Anabaptist pastor Thomas Müntzer were defeated at the Battle of Frankenhausen, ending the German Peasants' War in the Holy Roman Empire.

Anne Boleyn, Queen of England, stands trial in London on charges of treason, adultery and incest; she is condemned to death by a specially-selected jury.

Mary, Queen of Scots marries James Hepburn, 4th Earl of Bothwell, her third husband.

Johannes Kepler confirms his previously rejected discovery of the third law of planetary motion (he first discovered it on March 8 but soon rejected the idea after some initial calculations were made).

The Treaty of Westphalia is signed.