1259 CE
Epirote–Nicaean conflict, Battle of Pelagonia: The Empire of Nicaea defeats the Principality of Achaea, ensuring the eventual reconquest of Constantinople in 1261. Kings Louis IX of France and Henry III of England agree to the Treaty of Paris, in which Henry renounces his claims to French-controlled territory on continental Europe (including Normandy), in exchange for Louis withdrawing his support for English rebels. Lannathai, a kingdom in the north of Thailand, is founded by King Mangrai.
Geopolitics & Diplomacy
- December 4 – Kings Louis IX of France and Henry III of England agree to the Treaty of Paris, in which Henry renounces his claims to French-controlled territory on continental Europe (including Normandy), in exchange for Louis withdrawing his support for English rebels.source
- The Chinese era Kaiqing begins and ends, in the Southern Song dynasty of China (Emperor Lizong).source
- The German cities of Lübeck, Wismar, and Rostock enter into a pact to defend against pirates of the Baltic Sea, laying the groundwork for the Hanseatic League.source
Conflict & Security
- March – The Japanese Shōka era ends, and the Shōgen era begins (till April 1260).source
- September – Epirote–Nicaean conflict, Battle of Pelagonia: The Empire of Nicaea defeats the Principality of Achaea, ensuring the eventual reconquest of Constantinople in 1261.source
- The Goryeo Kingdom in Korea surrenders to invading Mongol forces.source
- Nogai Khan leads the second Mongol Golden Horde attack against Lithuania, and Poland.source
Economy & Finance
- Lannathai, a kingdom in the north of Thailand, is founded by King Mangrai.source
Technology & Infrastructure
- While engaged in a war with the Mongols, the Song Chinese official Li Zengbo writes in his Kozhai Zagao, Xugaohou that the city of Qingzhou is manufacturing one to two thousand strong iron-cased gunpowder bomb shells a month, dispatching to Xiangyang and Yingzhou about ten to twenty thousand such bombs at a time.source
Culture & Society
- The famous frescoes of the Boyana Church in Bulgaria are completed (the church and its murals are now a UNESCO World Heritage Site).source
Births
- February 25 – Infanta Branca of Portugal, daughter of King Afonso III of Portugal and Urraca of Castile (d. 1321)source
- March 25 – Andronikos II Palaiologos, Byzantine emperor (d. 1332)source
- Demetre II of Georgia (d. 1289)source
- Richard Óg de Burgh, 2nd Earl of Ulster (d. 1326)source
- Pietro Cavallini, Italian painter (d. 1330)source
Deaths
- January – Matilda II of Boulogne, ruler of Boulogne, queen consort of Portugal (b. 1202)source
- February 7 – Thomas, Count of Flanderssource
- May 29 – King Christopher I of Denmark (b. 1219)source
- August 11 – Möngke Khan of the Mongol Empiresource
- October 7 – Ezzelino III da Romano, Italian rulersource
- November 18 – Adam Marsh, English scholar and theologiansource
- date unknown – Matthew Paris, English chroniclersource