Events

• 20 March – Pope Gregory IX excommunicates Frederick II, Holy Roman Emperor.

• Frederick II, Holy Roman Emperor conducts the Siege of Faenza.

• The main tower of Lincoln Cathedral collapses.

• Mongol invasion of Rus is in progress.

Births

• June 17 – King Edward I of England (d. 1307)

• December 17 – Kujo Yoritsugu, Japanese shogun (d. 1256)

• Peter III of Aragon (d. 1285)

• John II, Duke of Brittany (d. 1305)

• Ippen, Japanese monk (d. 1289)

Deaths

• March 3 – Vladimir III Rurikovich, Grand Prince of Kiev (b. 1187)

• March 20 – Hermann von Salza, fourth Grand Master of the Teutonic Knights

• March 28 – Emperor Go-Toba of Japan (b. 1180)

• Cormac mac Art O Melaghlain, King of Meath