1255

Millennium:	2nd millennium
Centuries:	12th century – 13th century – 14th century
Decades:	1220s  1230s  1240s  – 1250s –  1260s  1270s  1280s
Years:	1252 1253 1254 – 1255 – 1256 1257 1258

Events

Europe

Western Europe

• August – The final Cathar stronghold in southern France falls, eliminating the last refuge of the heretical Cathars after the Roman Catholic Church engaged in a program to crush the sect, starting in 1209 with the Albigensian Crusade.
• The death of Little Saint Hugh of Lincoln prompts persecution of Jews in England on accusations of blood libel.
• Lisbon becomes the capital of the Kingdom of Portugal.
• The Gothic cathedral at Bourges, France, is completed. It is now a UNESCO World Heritage Site.
• A survey of royal privileges is conducted, which is included in the Hundred Rolls, an English census seen as a follow up to the Domesday Book completed in 1086; the Hundred Rolls is later completed with two larger surveys in 1274/1275 and 1279/1280.

Central and Eastern Europe

• May – William of Rubruck from Constantinople returns to Cyprus from his missionary journey to convert the Tatars of central and eastern Asia, his efforts having been unsuccessful.
• Königsberg (now Kaliningrad) is founded in Prussia.
• Theodore II Lascaris, Byzantine Emperor (in exile in the Empire of Nicaea), conducts a military campaign to recover Thrace from the Bulgarians. He concludes the task successfully a year later in 1256.
• The Duchy of Bavaria is split into Upper and Lower Bavaria
• The German state of Nassau is divided, not to be reunited until 1806.
• King Béla IV of Hungary grants Banská Bystrica municipal rights of a royal town.

Asia

• Hulagu Khan is dispatched by his brother Möngke Khan to destroy the remaining Muslim states in southwestern Asia.

Births

• Albert I of Germany, Holy Roman Emperor (died 1308)
• William de Ros, 2nd Baron de Ros, claimant to the crown of Scotland (died 1317)
• Duccio di Buoninsegna, Sienese painter (died 1319)
• Grand Prince Andrey of Gorodets (approximate date; died 1304)
• Adolf of Nassau-Weilburg, King of the Romans (approximate date; died 1298)

Deaths

• May 1 – Walter de Gray, English prelate and statesman
• Little Saint Hugh of Lincoln (born 1247)
• Jarler, Archbishop of Sweden
• Sundiata Keita, semi-historical hero and founder of the Mali Empire. (approximate date; born c. 1190)
• Batu Khan, Mongol ruler and founder of the Blue Horde.