1204
Year 1204 was a leap year starting on Thursday of the Julian calendar.
Events
- January 27-28 - Byzantine emperor Alexios IV Angelos is overthrown in a revolution.
- February 5 - Alexios V Doukas is crowned Byzantine emperor.Image:ConquestOfConstantinopleByTheCrusadersIn1204.jpg|thumb|right|150px|Conquest of Constantinople by the Crusaders
- April 12 - Sack of Constantinople: Crusaders enter Constantinople by storm and start pillaging the city as part of the Fourth Crusade. Forces of the Republic of Venice seize the antique statues that will become the horses of Saint Mark.
- 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.
- Theodore I Laskaris 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 I, Marquis 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.
- Tsar Kaloyan is recognized as king of Bulgaria by Pope Innocent III, after the creation of the Bulgarian Uniate church.
- Valdemar II of Denmark is recognized as king in Norway.
- Angers and Normandy are captured by Philip II of France.
- The Cistercian convent of Port-Royal-des-Champs is established.
- The district of Cham becomes subject to Bavaria.
- Hermann I, Landgrave of Thuringia submits to Philip of Swabia.
- Beaulieu Abbey is founded.
- The Channel Islands of Guernsey and Jersey decide, after a plebiscite of wealthy land owners, to remain with the English crown, after Normandy is recaptured by Philip II of France.