1250

By place

World

• The world population is estimated at between 400 and 416 million individuals.
• World climate transitions from the Medieval Warm Period to the Little Ice Age.
• Medieval music: The Notre Dame school of polyphony ends.

Europe

• February 2 – King Eric XI (Eriksson) dies and is succeeded by the 10-year-old Valdemar I, who is the eldest son of Birger jarl. He is elected as ruler of Sweden, and becomes the first Swedish king of the House of Folkung.
• October 12 – A great storm shifts the mouth of the River Rother in England 12 miles (20 km) to the west; a battering series of strong storms significantly alters other coastal geography around Romney Marsh.
• December 13 – Emperor Frederick II dies, beginning the 23-year-long "Great Interregnum". Frederick is the last Holy Roman Emperor of the Hohenstaufen dynasty; after the interregnum, the empire passes to the Habsburgs.
• The Lombard League dissolves upon the death of its member states' nemesis, Frederick II, Holy Roman Emperor.
• King Afonso III (the Boulonnais) captures the Algarve from the Moors, thus completing the expulsion of the Moors from Portugal.
• Albertus Magnus isolates the element arsenic, as the 8th discovered metal. He also first uses the word "oriole" to describe a type of bird (most likely the golden oriole).
• The Rialto Bridge in Venice (in modern-day Italy) is converted from a pontoon bridge to a permanent, raised wooden structure.
• The Ponts Couverts fortified bridges of Strasbourg (in modern-day France) are completed.
• Vincent of Beauvais completes his proto-encyclopedic work Speculum Maius ("Greater mirror").
• The first of the Parlements of Ancien Régime France is established.
• Villard de Honnecourt draws the first known image of a sawmill.
• The first usage is made of the English word "cuckold", according to the Oxford English Dictionary.

Asia

• July 9 – The Qaymariyya tribe engineers a coup d'état to hand over Damascus to An-Nasir Yusuf. The garrison in the citadel surrenders later to him.
• A kurultai is called by Batu Khan in Siberia as part of maneuverings which will elect Möngke Khan as khan of the Mongol Empire in 1251.
• Starting in this year and ending in 1275, the Muslim Shougeng Pu, likely a Persian or an Arab, serves as the Commissioner of Merchant Shipping for the Song dynasty Chinese seaport at Quanzhou, due to his effort in defeating pirates.

Africa

• April 8 – Battle of Fariskur: Louis IX (the Saint) is captured by Baibars' Mamluk army while he is in Egypt conducting the Seventh Crusade; he later has to ransom himself.
• April 30 – King Louis IX (the Saint) is released by his Egyptian captors after paying a ransom of one million dinars and turning over the city of Damietta.
• May 2 – Al-Muazzam Turanshah, Ayyubid ruler of Egypt, is murdered, ending effective Ayyubid Dynasty rule in the country. He is briefly succeeded by his widow, Sultana Shajar al-Durr.
• July 21 – Aybak becomes ruler of Egypt, beginning the Bahri Dynasty of the Mamluk Sultanate. After 5 days he stands down and the 6-year-old Al-Ashraf Musa is nominally proclaimed sultan.
• The Welayta state is founded in modern-day Ethiopia.
• In Tunis, a popular rebellion against newly arrived, wealthy and influential Andalusian refugees breaks out, and is violently put down.

Oceania

• Samoa frees itself from Tongan rule, which begins the Malietoa dynasty in Samoa (approximate date).

By topic

Markets

• The Flemish town of Douai emits the first recorded redeemable annuities in medieval Europe, confirming a trend of consolidation of local public debt started in 1218, in Rheims.
• The Sienese bankers belonging to the firm known as the Gran Tavola, under the steering of the Bonsignori Brothers, become the main financiers of the Papacy.

• April 8 – John Tristan, son of Louis IX (d. 1270)
• Adolf II of Waldeck, prince-bishop of Liège (d. 1302)
• Agnes of Baden, German noblewoman (d. 1295)
• Albert II of Saxony, German nobleman (d. 1298)
• Albert III, German nobleman and knight (d. 1300)
• Albertus de Chiavari, Italian Master General (d. 1300)
• Allamah al-Hilli, Persian Shia theologian (d. 1325)
• Asher ben Jehiel, German Jewish rabbi (d. 1327)
• Beatrice of Savoy, Swiss noblewoman (d. 1292)
• Bonconte I da Montefeltro, Italian general (d. 1289)
• Diether of Nassau, archbishop of Trier (d. 1307)
• Dmitry of Pereslavl, Kievan Grand Prince (d. 1294)
• Esclaramunda of Foix, queen of Majorca (d. 1315)
• Fra Dolcino, Italian priest and reformist (d. 1307)
• Grigorije II of Ras, Serbian monk-scribe (d. 1321)
• Guido Cavalcanti, Italian poet and writer (d. 1300)
• Jeanne de Montfort, Swiss noblewoman (d. 1300)
• John IV (Laskaris), emperor of Nicaea (d. 1305)
• Konrad II of Masovia, Polish nobleman (d. 1294)
• Margaret of Burgundy, queen of Sicily (d. 1308)
• Matteo I Visconti, Italian imperial vicar (d. 1322)
• Mordechai ben Hillel, German scholar (d. 1298)
• Nijō Tameyo, Japanese official and poet (d. 1338)
• Niklot I, German nobleman and knight (d. 1323)
• Rhys ap Maredudd, Welsh nobleman (d. 1292)
• Robert II, French nobleman and knight (d. 1302)
• Sancho of Aragon, Spanish archbishop (d. 1275)
• Theodoric of Freiberg, German physicist (d. 1311)
• Záviš of Falkenstein, Bohemian nobleman (d. 1290)

• February 2 – Eric XI (Eriksson), king of Sweden (b. 1216)
• February 6 – Geoffrey VI, French nobleman and knight
• February 8
  • Andrew III, French nobleman and knight (b. 1200)
  • Fakhr ad-Din, Egyptian ruler and military leader
  • Robert I (the Good), French nobleman (b. 1216)
  • William Longespée (the Younger), English knight
• February 11 – Jean de Ronay, French Grand Master
• March 29 – Ludolph of Ratzeburg, German bishop
• April 6
  • Guillaume de Sonnac, French Grand Master
  • Hugh XI of Lusignan, French nobleman (b. 1221)
• May 2 – Al-Muazzam Turanshah, Ayyubid ruler of Egypt
• May 21 – Humbert V, French nobleman and knight (b. 1198)
• May 26 – Peter I (Mauclerc), French nobleman (b. 1187)
• May 27 – Raniero Capocci, Italian priest and cardinal
• June 7 – Vitslav I, Danish nobleman and knight (b. 1180)
• June 18 – Theresa of Portugal, queen of León (b. 1176)
• August 10 – Eric IV (Ploughpenny), king of Denmark
• October 4 – Herman VI, German nobleman and knight
• October 12 – Richard Wendene, English bishop (b. 1219)
• December 13 – Frederick II, Holy Roman Emperor (b. 1194)
• Alice of Schaerbeek, Flemish Cistercian lay sister (b. 1220)
• Gilbertus Anglicus, English physician and writer (b. 1180)
• Julian of Speyer, German Franciscan composer and poet
• Leonardo of Pisa, Italian mathematician and writer (b. 1170)
• Romée de Villeneuve, French nobleman and seneschal
• Shihab al-Din Muhammad al-Nasawi, Persian biographer
• Walter of Serviliano, Italian Benedictine hermit and abbot
• Yang Miaozhen, Chinese female military leader (b. 1193)