|Centuries:||12th century – 13th century – 14th century|
|Decades:||1220s 1230s 1240s – 1250s – 1260s 1270s 1280s|
|Years:||1253 1254 1255 – 1256 – 1257 1258 1259|
|1256 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishments and disestablishments categories|
|Establishments – Disestablishments|
|Art and literature|
|1256 in poetry|
|Ab urbe condita||2009|
|English Regnal year||40 Hen. 3 – 41 Hen. 3|
— to —丙辰年十二月十三日
|- Vikram Samvat||1312–1313|
|- Shaka Samvat||1178–1179|
|- Kali Yuga||4357–4358|
|- Ǹrí Ìgbò||256–257|
|Juche calendar||N/A (before 1912)|
|Julian calendar||1256 MCCLVI|
|Minguo calendar||656 before ROC
|Thai solar calendar||1799|
|Wikimedia Commons has media related to: 1256|
By place 
- May 4 – Pope Alexander IV issues the papal bull Licet ecclesiae catholicae, constituting the Order of Saint Augustine 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.
- Church of Santa Costanza, Rome, is consecrated as a church.
- The ancient Irish Kingdom of Breifne splits into East Breifne and West Breifne after a war between the O'Reillys and the O'Rourkes.
- 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 (d. 1317)
- Ibn al-Banna, Arabian mathematician (d. 1321)
- 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)
- September 21 – William of Kilkenny, Lord Chancellor of England
- October 14 – Kujo Yoritsugu, Japanese shogun (b. 1239)
- Johannes de Sacrobosco, English scholar