September 13, 1229: Ögedei succeeds Genghis Khan as Khagan of the Mongol Empire.
Upon his death in 1227, Genghis Khan, founder and first ruler of the Mongol Empire, passed his title and his lands - which at the time of his death spanned an area twice the size of the Roman Empire - to his third son, Ögedei. As famous as Genghis Khan was as a conqueror, the Mongol Empire expanded even further during Ögedei’s twelve year reign, stretching into Central Europe and Russia.
Ögedei was formally elected to succeed his father by a kurultai (a kind of military-political decision-making assembly), and by their decree he was proclaimed Khagan - emperor, king of kings. His mostly stable reign was marked by a continuation of Genghis Khan’s legacy; it was also marked by a series of military exploits and conquest. In 1231, the Mongol Empire launched an invasion of the Korean Peninsula that was to last until after Ögedei’s own death, ending in Goryeo’s surrender. In 1237 an invasion of Russia led by the Great Khan’s nephew Batu was launched, resulting in the disintegration of Kievan Rus’, and enormous repercussions (both short- and long-term) for the development of the region and its inhabitants.