The 1260s is the decade starting January 1, 1260 and ending December 31, 1269.
In Asia, Kublai Khan was proclaimed the supreme leader of the Mongol Empire, although his title was only partially recognized. After defeating his younger brother Ariq Böke, he moved his capital to Beijing; while he fought the southern Chinese Song Dynasty, the empire saw its first significant military defeats — first in Palestine at the hands of the Mamluks of Egypt, and later in the Caucasus. The Mamluks, led by their new sultan Baibars, quickly became a regional power in the Middle East by capturing a number of crusader states and repulsing Mongol attacks. The Empire of Nicaea succeeded in capturing Constantinople and the rest of the Latin Empire, thus re-establishing the Byzantine Empire.
In Europe, political strife and territorial disputes led to widespread warfare around the continent. England witnessed the Second Barons' War, a civil war fought over the aristocracy's disillusionment with King Henry III's attempts to maintain an absolute monarchy. The pope of the Catholic Church, aligned against the Hohenstaufen dynasty of the Holy Roman Emperor, succeeded in eliminating the line when the last male heir, Conradin, was killed by papal ally Charles I of Sicily, a Frenchman. Meanwhile, King Otakar II of Bohemia became the most powerful prince in Europe, expanding his territories through both warfare and inheritance. In other developments, both Iceland and Greenland accepted the overlordship of Norway, but Scotland was able to repulse a Norse invasion and broker a favorable peace settlement. In Spain, the Reconquista continued as several important cities were recaptured from the Moors. Political reforms were instituted in the election procedures of the pope and the doges of Venice, and the parliaments of Ireland and England met for the first time.
Several important cultural achievements were made in the decade, including publication of Roger Bacon's important scientific work Opus Majus and Thomas Aquinas' Summa contra Gentiles. Masterpieces of architecture and sculpture were completed at cathedrals around Europe, including the Cathedral of Chartres and Nicola Pisano's pulpits for the Duomo di Siena and Pisa's Baptistery. In religion, the Sukhothai kingdom in Thailand adopted Buddhism as its official religion. In Europe anti-Semitism intensified, as several authorities promulgated laws requiring Jews to wear identifying yellow badges, Jews were massacred in England, and the Talmud was attacked and censored by the Catholic Church.
War and politics
War and peace
North and West Europe
Central and South Europe
England: The Second Barons' War
- 1261 – King Henry III of England obtains a papal bull releasing him from the Provisions of Oxford, setting the stage for a civil war over the power struggle between the crown and the aristocracy of England.
- 1264 – Before May – Second Barons' War, an English civil war, begins.
- 1264 – May 12 to May 14 – The Battle of Lewes 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".
- 1265 – January 20 – In Westminster, the first English parliament conducts its first meeting in the Palace of Westminster, now also known as the Houses of Parliament.
- 1265 – Before August – Future King Edward I escapes captivity in the hands of Simon de Montfort.
- 1265 – August 4 – The Battle of Evesham is fought in Worcestershire, with the army of Edward defeating the forces of rebellious barons led by Simon de Montfort and killing de Montfort and many of his allies. This is sometimes considered the death of chivalry in England.
- 1266 – October – The war winds down as supporters of the slain rebel leader Simon de Montfort make an offer of peace to the king in the Dictum of Kenilworth.
- 1267 – The Second Barons' War ends, as the rebels and King Henry III of England agree to peace terms as laid out in the Dictum of Kenilworth.
- 1262 – King Mindaugas of Lithuania renounces Christianity, returning to his pagan roots and reverting to Grand Duke of Lithuania.
- 1263 – Mindaugas, the only Christian king of Lithuania, is assassinated by his cousin Treniota.
- 1264 – In the Peerage of England, the title Baron de Ros, the oldest continuously held peerage title in England, is created by writ of summons.
- 1267 – King Henry III of England acknowledges Llywelyn ap Gruffudd's title of Prince of Wales in the Treaty of Montgomery.
- 1268 – October 29 – Conradin, the last legitimate male heir of the Hohenstaufen dynasty of Kings of Germany and Holy Roman Emperors, is executed along with his companion Frederick I, Margrave of Baden by Charles I of Sicily, a political rival and ally to the hostile Catholic church.
- 1268 – The House of Bourbon first rises to prominence with the marriage of Robert, Count of Clermont, Louis IX of France's son, to Duke Hugh IV of Burgundy's granddaughter, Beatrice of Burgundy, heiress to the lordship of Bourbon.
- 1269 – King Otakar II of Bohemia inherits the Duchy of Carinthia and part of Carniola, making him the most powerful prince within the Holy Roman Empire.
Asia and Africa
Mamluk sultanate of Egypt