Events

• April 9 – Peter of Courtenay is crowned emperor of the Latin Empire of Constantinople at Rome, by Pope Honorius III.

• May 20 – First Barons' War: The royalists prevail at Lincoln.

• August 24 – First Barons' War: In the Battle of Sandwich between English and French soldiers in the English Channel, mercenary Eustace the Monk, working for the French side, is captured and beheaded.

• September 11 – The Treaty of Lambeth ends the First Barons' War.

• September 21 – Battle of St. Matthew's Day: The Germans defeat the Estonians.

• The Kingdom of Serbia is founded.

• The Fifth Crusade begins with a failed Christian attack on Egypt.

• Genghis Khan destroys Kara-Khitai.

• England decrees that only Englishman can be clergy of Ireland.

• Mukhali is back in Genghis Khan's camp in Mongolia and receives the hereditary title of prince, a golden seal, and a white standard with 9 tails and a black crescent in the middle. He is appointed commander in chief of operations in North China.

Births

• John I, Duke of Brittany (d. 1286)

• Baldwin, Latin Emperor of Constantinople (d. 1273)

• Henry I of Cyprus

• Eleanor of Provence, Queen of Henry III of England (d. 1291)

• Hulagu Khan, Mongol ruler of Persia (d. 1265)

• Boniface of Savoy, Archbishop of Canterbury (d. 1270)

Deaths

• April 23 – Inge II of Norway (b. 1185)

• April 25 – Hermann I, Landgrave of Thuringia

• August 24 – Eustace the Monk, French mercenary and pirate

• September 10 – William de Reviers, 5th Earl of Devon, English nobleman

• September 21 – Lembitu of Lehola, Estonian resistance leader and Caupo of Turaida, Livonian leader (at the Battle of St. Matthew's Day)

• October 14 – Isabel of Gloucester, wife of King John of England

• Maria Comnena, wife of Amalric I of Jerusalem

• Lovers Of Teruel – Juan Martinez (aka Diego Marcilla) & Isabel Segura