Ögedei Khagan (also Ogodei; 1186 – 11 December 1241) was second khagan of the Mongol Empire. The third son of Genghis Khan, he continued the expansion of the empire that his father had begun.
Born in 1186 AD, Ögedei fought in numerous battles during his father's rise to power. After being granted a large appanage and taking a number of wives, including Töregene, he played a prominent role in the Mongol invasion of the Khwarazmian Empire. When his older brothers Jochi and Chagatai quarrelled over strategies when besieging Gurganj, Genghis appointed Ögedei sole commander; his successful capture of the city in 1221 ensured his military reputation. He was confirmed as heir after further infighting between his elder brothers led to both being excluded from succession plans. Genghis died in 1227, and Ögedei was elected as khagan in 1229, after a two-year regency led by his younger brother Tolui.
As khan, Ögedei pursued the expansionist policies of his father. He launched a second invasion of Persia led by Chormaqan Noyan in 1230, which subdued the Khwarazmian prince Jalal al-Din and began to subjugate Georgia. He initiated the Mongol invasions of Korea, and his armies skirmished with the Song dynasty and in India. By the time of his death in 1241, large armies under the command of his nephew Batu Khan and Subutai had subdued the steppes and penetrated deep into Europe. These armies defeated Poland at Legnica and Hungary at Mohi before retreating. It is likely that this retreat was caused by the need to find a successor after Ögedei's death, although some scholars have speculated that the Mongols were simply unable to invade further because of logistical difficulties.
As an administrator, Ögedei continued to develop the fast-growing Mongol state. Working with officials such as Yelü Chucai, he developed ortogh trading systems, instituted methods of tax collection, and established regional bureaucracies which controlled legal and economic affairs. He also founded the Mongol capital city, Karakorum, in the 1230s.