Events

• Damietta is besieged by the knights of the Fifth Crusade.
• Livonian Brothers of the Sword begin to conquer Estonia.
• Minamoto no Sanetomo becomes Udaijin of Japan.
• Alfonso IX of Castile founds a university in Salamanca.

Ongoing events

• Fifth Crusade (1217-1221)

Births

• Emperor Chukyo of Japan
• September 1 - Kujo Yoritsune, fourth shogun of the Kamakura shogunate
• May 1 - Rudolph I of Germany, Holy Roman Emperor

Deaths

• Otto IV, Holy Roman Emperor
• June 25 - Simon de Montfort, 5th Earl of Leicester (b. 1160)