1211

Events 
 The oldest extant double entry bookkeeping record dates from 1211
 Canons regular of the Order of the Holy Cross founded September 14 1211
 Troops led by Estonian resistance fighter Lembitu of Lehola destroy a garrison of missionaries in the historical Estonian region of Sakala and raid the Russian town of Pskov.
 Mongol forces under Genghis Khan invade Jin China, aiming at this stage simply to loot the countryside. A Chinese army is defeated and slaughtered at the Battle of the Badger's Mouth near Zhangjiakou and another is beaten at Mukden, where the city is taken. Beijing is also besieged by the Mongol hordes.
 Church at the French city of Reims burns down; soon after, construction begins on the cathedral, Notre Dame de Reims.

 Births 
 Ibn Khallikan, Muslim scholar

 Deaths 
 August 9 – William de Braose, 4th Lord of Bramber

 Monarchs/Presidents 
 France – Philippe II, Auguste King of France (reigned from 1180 to 1223)
 Mongol Empire – Genghis Khan, Mongol Khan (from 1206 to 1227)
 Venice – Pietro Ziani Doge of Venice (ruled from 1205 to 1229)