1234

Year 1234 (MCCXXXIV) was a common year starting on Sunday (full calendar displayed in the link) of the Julian calendar.

• King Canute II of Sweden ("the Tall") dies after a five-year reign. His rival, Eric XI ("the Lisp and Lame"), returns as ruler of Sweden (possibly after a civil war between the two of them). It is also possible that Canute dies of natural causes, and Eric peacefully then returns as king.
• King Andrew II of Hungary proclaims his son, Coloman of Galicia, as ruler (or ban) of Bosnia, who passes it on to Prijezda, a cousin of Matej Ninoslav, despite Matej being the legitimate ruler.
• Reconquista: King Sancho II of Portugal conquers the cities of Aljustrel and Mértola from the Moors.^[1]

• February 9 – Mongol conquest of the Jin dynasty: The Mongol army led by Ögedei Khan captures the Jin capital at Caizhou, after the two-month Siege of Caizhou). Emperor Aizong of Jin abdicates the throne to Wanyan Chenglin, a descendant of the Jin imperial clan. After the Mongol and Song forces have breached the city walls, Aizong tries to escape, but commits suicide to avoid being captured. This marks the end of the Jin dynasty (1115–1234) ('Great Jin') in China.^[2]

• The Manden region rises against the Kaniaga Kingdom. This is the beginning of a process that will lead to the rise of the Mali Empire.^[3]

• November – Pope Gregory IX proclaims war on the city of Rome after a local revolt forces him into exile.^[4] He issues the papal bull Rachel suum videns, calling for a new crusade to the Holy Land.^[5]
• Lund Cathedral in Sweden is heavily damaged in a catastrophic fire. Large donations are made to the church, to rebuild the cathedral.

• February 27 – Abaqa Khan, Mongol ruler of the Ilkhanate (d. 1282)
• Christina of Norway, Infanta of Castile, princess (d. 1262)
• Kaliman I, emperor (tsar) of Bulgaria (d. 1246)
• Conrad of Ascoli, Italian friar and missionary (d. 1289)
• Ippen (or Zuien), Japanese Buddhist monk (d. 1289)
• Manuel of Castile, Spanish prince (infante) (d. 1283)
• Margaret of Holland, Dutch noblewoman (d. 1276)
• Ou Shizi, Chinese Confucian scholar (d. 1324)

• January 7 – Robert of Auvergne, bishop of Clermont
• February 9
  • Aizong of Jin, Chinese emperor (b. 1198)
  • Mo of Jin (or Hudun), Chinese emperor
• April 7 – Sancho VII ("the Strong"), king of Navarre
• April 16 – Richard Marshal, 3rd Earl of Pembroke, English nobleman (b. 1191)
• May 7 – Otto I, Duke of Merania, German nobleman and knight (b. 1180)
• June 18 – Chūkyō, emperor (tennō) of Japan (b. 1218)
• July 19 – Floris IV, Count of Holland, Dutch nobleman and knight (b. 1210)
• July 29 – William Pinchon, French prelate and bishop
• August 7 – Hugh Foliot, bishop of Hereford (b. 1155)
• August 31 – Go-Horikawa, emperor of Japan (b. 1212)
• September 6 – Milo of Nanteuil, bishop of Beauvais
• September 26 – Eudes II, Lord of Ham, French nobleman
• November 8 – Baha ad-Din ibn Shaddad, Arab historian (b. 1145)
• Abu Muhammad Salih al-Majiri, Almohad Sufi leader (b. 1155)
• Alan of Galloway, Scottish nobleman
• Canute II ("the Tall"), king of Sweden (House of Folkung)
• Dalfi d'Alvernha, Count of Clermont and Montferrand, French nobleman, troubador and patron of the arts (b. c. 1150)
• Helen of Galloway, Scottish noblewoman and heiress
• Hugh de Neville, English Chief Forester and sheriff
• Ibn al-Farid, Arab poet, writer and philosopher (b. 1181)
• Minamoto no Ienaga, Japanese waka poet (b. 1170)
• Nasir ad-Din Mahmud II, Zengid ruler
• Pacificus, Italian-born friar and poet
• Renard II of Dampierre-en-Astenois (or Renaud), French nobleman and knight
• Rhys Gryg (Rhys ap Rhys), Welsh prince of Deheubarth
• Robert III, Count of Dreux ("Gasteblé"), French nobleman (b. 1185)
• Shihab al-Din 'Umar al-Suhrawardi, Persian Sufi scholar (b. 1145)
• William of Andres, French abbot and historian
• Zhang Yuansu, Chinese physician and writer