1255

For broader historical context, see 13th century.

align="center" colspan=2 | Years:
1252 1253 1254 - 1255 - 1256 1257 1258

align="center" colspan=2 | Decades:
1220s 1230s 1240s - 1250s - 1260s 1270s 1280s

align="center" | Centuries:
12th century - 13th century - 14th century

Events

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.
The Portuguese capital is moved to Lisbon.
The Gothic cathedral at Bourges, France, is completed. It is now a UNESCO World Heritage Site.

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.
Knigsberg (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.

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