1261

Events

* January - Pope Alexander III bans the Flagellants movement.
* July 25 - The city of Constantinople is recaptured by Nicaean forces under the command of Alexios Strategopoulos, thus re-establishing the Byzantine Empire.
* 15 August - Michael VIII Palaeologus is crowned Byzantine emperor in Constantinople.
* August 29 - Pope Urban IV succeeds Pope Alexander III as the 182nd pope, the last man to do so without being a cardinal first.
* The population of Greenland accepts the overlordship of the King of Norway.
* The Japanese Bun'ō era ends, and the Kōchō era begins.
* The Convent of Wurmsbach is established in Switzerland.
* Baibars establishes a puppet caliphate in Cairo.
* Bela IV of Hungary repels a Tatar invasion.
* The Mongol Khagan, Kublai Khan, releases 75 Song Dynasty Chinese merchants from captivity after they had been captured along the border of the Mongol Empire and the Chinese Southern Song Dynasty. This is an act to increase his reputation amongst the Chinese, shore up his legitimacy as a just ruler, and to gain more defectors from the Southern Song Dynasty.
* The earliest extant Chinese illustration of 'Pascal's Triangle' is from Yang Hui's book "Xiangjie Jiuzhang Suanfa", published in this year, although knowledge of Pascal's Triangle existed in China by at least 1100.

Births

* February 1 - Walter de Stapledon, English bishop (d. 1326)
* October 9 - King Denis of Portugal (d. 1325)
* Daniel of Moscow, son of Alexander Nevsky

Deaths

* February 28 - Henry III, Duke of Brabant
* May 25 - Pope Alexander IV
* September 18 - Konrad von Hochstaden, Archbishop of Cologne
* Plaisance of Antioch, regent
* Qin Jiushao, Chinese mathematician of the Song Dynasty (b. 1202)