Events

• February – Byzantine emperor Alexius IV is overthrown in a revolution, and Alexius V is proclaimed emperor.

• April 13 – Fourth Crusade: The Crusaders take Constantinople by storm, and pillage the city for 3 days.

• May 16 – Baldwin, Count of Flanders is crowned emperor of the Latin Empire a week after his election by the members of the Fourth Crusade.

• The Republic of Croatia becomes Hungary and Venice intermittently.

• Theodore I Lascaris flees to Nicaea after the capture of Constantinople, and establishes the Empire of Nicaea; Byzantine successor states are also established in Epirus and Trebizond.

• Boniface of Montferrat, a leader of the Fourth Crusade, founds the Kingdom of Thessalonica.

• The writings of French theologian Amalric of Bena are condemned by the University of Paris and Pope Innocent III.

• Valdemar II, King of Denmark, is recognized as king in Norway.

• Angers and Normandy are captured by Philip II of France.

• The Cistercian convent of Port-Royal is established.

• The district of Cham becomes subject to Bavaria.

• Hermann I of Thuringia submits to Philip of Swabia.

• Beaulieu Abbey is founded.

• Guernsey and Jersey decide, after a plebiscite of wealthy land owners, to remain with the English crown after Normandy was recaptured by Philip II of France.

• Pope Innocent III proclaims the Albigensian Crusade against the Cathars of Languedoc.

Births

• Haakon IV, King of Norway (d. 1263)

• Heinrich Raspe, Landgraf of Thuringia (d. 1247)

• Abû 'Uthmân Sa'îd Hakam al Qurashi, Ra'îs of Manûrqa (d. 1282)

Deaths

• January 1 – King Haakon III of Norway

• February 8 – Alexius IV Angelus, Byzantine Emperor

• April 1 – Eleanor of Aquitaine, queen of France and England

• August 11 – King Guttorm of Norway

• August 14 – Minamoto no Yoriie, Japanese shogun (b. 1182)

• October 21 – Robert de Beaumont, 4th Earl of Leicester, English nobleman

• December 13 – Maimonides, Spanish rabbi and philosopher (b. 1135)

• Ban Kulin – ruler of Bosnia (b. 1163)

• Amalric of Bena, French theologian

• William de Burgh, English politician

• Emeric of Hungary (b. 1174)

• Isaac II Angelus, Byzantine Emperor

• Suleiman II of Rum