1256

Events

Europe

* May 4 - Pope Alexander IV issues the papal bull "Licet ecclesiae catholicae", constituting the Augustinian monastic order at Lecceto Monastery.
* The city of Lviv, in present-day Ukraine, is founded by Danylo King of Rus.
* Theodore II Lascaris, Byzantine Emperor (in exile in the Empire of Nicaea), successfully concludes a military campaign started a year earlier to recover Thrace from the Bulgarians.
* Abingdon School is founded.
* Roger Bacon becomes a Franciscan Friar.

Asia

* October - Mongol commander Baiju (operating under Hulagu Khan's command) leads his forces in a victory over Kay Ka'us II of the Sultanate of Rüm, thereby capturing Anatolia.
* December 15 - Hulagu Khan captures and destroys the Hashshashin stronghold at Alamut in present-day Iran.
* Hulagu Khan establishes the Ilkhanate dynasty of Persia, which will become one of four main divisions of the Mongol Empire.
* The Japanese Kenchō era ends, and the Kōgen era begins.

Births

* January 6 - Gertrude the Great, German mystic
* Robert, Count of Clermont, French founder of the House of Bourbon (d. 1317)

* Ibn al-Banna, Arab mathematician (d. 1321)

Deaths

* January 28 - William II, Count of Holland, King of Germany
* June 13 – Tankei, Japanese sculptor (b. 1173)
* September 1 - Kujo Yoritsune, Japanese shogun (b. 1218)
* October 14 - Kujo Yoritsugu, Japanese shogun (b. 1239)
* William of Kilkenny, Lord Chancellor of England
* Johannes de Sacrobosco, English scholar