|Centuries:||12th century – 13th century – 14th century|
|Decades:||1220s 1230s 1240s – 1250s – 1260s 1270s 1280s|
|Years:||1253 1254 1255 – 1256 – 1257 1258 1259|
- May 4 – Pope Alexander IV issues a 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.
- 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.
- January 6 – Gertrude the Great, German mystic
- Robert, Count of Clermont, French founder of the House of Bourbon (died 1317)
- January 28 – William II, Count of Holland, King of Germany
- June 13 – Tankei, Japanese sculptor (born 1173)
- September 1 – Kujo Yoritsune, Japanese shogun (born 1218)
- October 14 – Kujo Yoritsugu, Japanese shogun (born 1239)
- William of Kilkenny, Lord Chancellor of England
- Johannes de Sacrobosco, English scholar