- Feb 2 Eric XI of Sweden (1222–29 and 1234–50), last of the house of Eric, dies at 33 or 34
- Feb 8 Robert I of Artois, French crusader (b. 1216)
- Feb 8 William II Longespee, dies as a martyr at the battle of Al Mansurah, Egypt (7th Crusade)
- May 2 Toeransa, sultan of Egypt, murdered
- Aug 9 King Eric IV of Denmark (1241-1250), beheaded after being betrayed by his brother (b. 1216)
- Aug 10 Erik IV Plovpenning, king of Denmark, murdered
- Oct 4 Herman VI, Margrave of Baden
- Dec 13 Frederick II, Holy Roman Emperor (1220-50), King of the Romans (Germany), dies at 55
Assassination
Drug Overdose
Gunshot Wound
Murder
Plane Crash
Suicide