1264

For broader historical context, see 1260s and 13th century.

Years: 1261 1262 1263 - 1264 - 1265 1266 1267
Decades: 1230s 1240s 1250s - 1260s - 1270s 1280s 1290s
Centuries: 12th century - 13th century - 14th century 1264 state leaders

Events

Before May - Second Barons' War, a civil war in England, begins.
May 12 to May 14 - The Battle of Lewes of the Second Barons' War is fought between Simon de Montfort, 6th Earl of Leicester and King Henry III of England in Sussex. By the end of the battle, de Montfort's forces capture both King Henry and his brother, future King Edward I, making de Montfort the "uncrowned king of England" for 15 months before Edward escapes captivity and recaptures the throne.
June 18 - The Parliament of Ireland meets at Castledermot in County Kildare, the first definitively known meeting of this Irish legislature.
In Spain, King James I of Aragon reconquers the cities of Orihuela in Alicante and Elx in Valencia from the Moors, ending over 500 years of Islamic rule.
The Thuringian War of Succession ends.
The state of Hesse gains its independence from Thuringia and becomes a free state of the Holy Roman Empire.
In the Peerage of England, the title Baron de Ros, the oldest continuously held peerage title in England, is created by writ of summons.

April - Gilbert de Clare, 7th Earl of Hertford leads a massacre of the Jews at Canterbury.
August 5 - Anti-Jewish riots in Arnstadt (modern-day Germany)
September 14 - Walter de Merton formally completes the foundation of the House of Scholars of Merton (later Merton College, Oxford) to provide education in Malden and the University of Oxford.
King Boleslaus V of Poland promulgates legal protection for his Jewish subjects, including protection from the kidnapping and forcible baptism of Jewish children.
In Barcelona, a commission of Dominicans censors portions of the Talmud for the first time by ordering the cancellation of passages found reprehensible from a Christian point of view.
Thomas Aquinas completes his theological work Summa contra Gentiles.

Kublai Khan, supreme leader of the Mongol Empire, moves the empire's capital from Karakorum in Mongolia to the Chinese city of Khanbaliq (now Beijing).
Kublai Khan defeats his brother and pretender to the title of khan, Ariq Boke, and takes him prisoner.