1256
Year 1256 was a leap year starting on Saturday of the Julian calendar.
Events
By place
Mongol Empire
- Spring - Mongol forces, under Hulagu Khan, cross the Oxus River, and begin their campaign to destroy the remaining Muslim states in southwestern Asia – with the first objectives being the Nizari Ismaili strongholds and Baghdad, the capital of the Abbasid Caliphate. The roads across Turkestan and Persia are repaired, and bridges built. Carts are requisitioned to bring siege machines from China.
- October - Mongol forces led by Baiju Noyan win a victory over Kaykaus II, Seljuk ruler of the Sultanate of Rum, and capture Anatolia. Kaykaus flees to the Byzantine court where he seeks refuge at Constantinople. The Empire of Trebizond fearing a potential punitive Mongol expedition, becomes a vassal state and is forced to pay a tribute tax every year in gold and silk.
- November 8-23 - Siege of Maymun-Diz: Mongol forces under Hulagu Khan successfully besiege the mountain castle of Maymun-Diz. Hulagu encircles the fortress and begins a bombardment for three days by mangonels from a nearby hilltop. On November 19, Nizari Isma'ili imam Rukn al-Din Khurshah surrenders, but a small part of the garrison refuses and fights a last stand, until they are killed after three days.
- December 15 - Mongol forces under Hulagu Khan capture and dismantle Alamut Castle after the surrender of the Nizari Ismaili leaders. Hulagu founds the Ilkhanate dynasty of Persia, which becomes one of the four main divisions of the Mongol Empire. The Nizari Ismaili government is disestablished; some of them migrate to Afghanistan, Badakhshan and Sindh.
Europe
- War of the Euboeote Succession: Achaean forces under William II of Villehardouin attempt to gain control of the island of Euboea, which is resisted by the local Lombard barons with the aid of the Republic of Venice. William launches devastating raids in Euboea. Guy I de la Roche, the "Great Lord" of Athens and Thebes, enters the war against William, along with other barons of Central Greece.
- 30 July – The Venetian Marsilio Zorzi recaptures Curzola in Dalmatia, and re-establishes himself as Count of Curzola and Mèleda.
British Isles
- Prince Llywelyn ap Gruffudd invades the northern coastal areas of Wales that agreed to English rule in 1254. The Lord Edward, who has been given the areas to govern himself by his father, King Henry III of England, asks him for support but Henry refuses.
- The ancient Irish Kingdom of Breifne splits into East Breifne and West Breifne, after a war between the O'Reillys and the O'Rourkes.
Levant
- War of Saint Sabas: A dispute between Venice and Genoa arises about concerning land in Acre owned by Mar Saba but claimed by both Venice and Genoa – which leads to a Genoese attack of the monastery in the Venetian quarter. The Venetians are supported by Pisa and the Knights Templar, while the Genoese are joined by the Knights Hospitaller.
By topic
Natural Disaster
- June 30 - A large volcanic eruption in Harrat Rahat is associated with an Islamic prophecy.
Religion
- May 4 - Pope Alexander IV issues the papal bull Licet ecclesiae catholicae, constituting the Order of Saint Augustine at Lecceto Monastery.
- August 25 - In Bologna, slavery and serfdom are abolished; this event is recorded in the document called Liber Paradisus.