|Centuries:||12th century – 13th century – 14th century|
|Decades:||1200s 1210s 1220s – 1230s – 1240s 1250s 1260s|
|Years:||1235 1236 1237 – 1238 – 1239 1240 1241|
- Battle of the Sit River was fought in the northern part of the present-day Yaroslavl Oblast of Russia between the Mongol Hordes of Batu Khan and the Russians under Yuri II of Vladimir during the Mongol invasion of Russia.
- In the Iberian peninsula, James I of Aragon captures the city of Valencia September 28 from the Moors; the Moors retreat to Granada.
- Mongols seize Moscow, at that time a small town.
- Peterborough Cathedral is consecrated.
- The Khmers are expelled from Luang Phrabang in Laos.
- The Sukhothai kingdom is founded in Thailand.
- The seat of the patriarchate of Aquileia is transferred to Udine.
- Simon de Montfort marries Eleanor, sister of Henry III of England.
- The Battle of Örlygsstaðir takes place – it is the largest armed conflict in the history of Iceland