Ogedei Khan (1185-11 December 1241) was the Khan of the Mongol Empire from 1229 to 1241, succeeding Tolui Khan and preceding Guyuk Khan. Ogedei was the third son of Genghis Khan, and during his reign he expanded the empire into Persia, new parts of China, and Europe.
Ogedei Khan was born sometime in 1185 to Genghis Khan (then Temujin) and his wife Borte. He was their third son, and he was old enough to take part in his father's campaigns, starting to hold command in 1211 during his father's war with the Great Jin dynasty of northern China. Ogedei was later transferred to Central Asia, leading his father's armies against Khwarezm and the other Muslim states, quelling a rebellion in Ghazni after a revolt in southeastern Persia and Afghanistan broke out. Ogedei was known as a good politician, and Genghis Khan chose him over Jochi Khan due to his possible illegitimacy and over Tolui Khan due to his excessive caution. Genghis died in 1227, and Tolui was regent until Ogedei was proclaimed Khan in 1229.
Ogedei commanded forces during the Mongol invasion of Central Asia, conquering the Persian cities of Hamadan and Qom, the latter of which became the capital of the Ilkhanate. Fars and Kerman peacefully surrendered, paying tribute instead of fighting the Mongols. From 1230 to 1237 he fought against the Great Jin, and in 1233 the Jin capital of Kaifeng fell after an intense siege. That same year, he crushed the Xi Xia, and in 1234 the Jin were wiped out after Caizhou's fall. In 1235 Ogedei seized Ganjak in present-day Azerbaijan, and he subdued Bagratid Armenia in 1238. In 1240 the Kingdom of Georgia surrendered, but it maintained its independence. By 1241, Goryeo had also fallen to the Mongols.
With the threats in Asia dealt with, Ogedei resumed his father's European campaigns that had stopped at the Black Sea in Russia by his 1227 death. Ogedei conquered all of Russia except for Novgorod, which became a vassal of the Mongols, having subdued Volga-Bulgaria, Alania, and the Kievan Rus. He sent Guyuk Khan to invade Europe while he briefly invaded India and Pakistan; in 1241, the Mongols won twin victories at Liegnitz and Mohi against Poland and Hungary, respectively. Ogedei wanted to push to the Atlantic Ocean and was launching a winter offensive against Vienna and Germany when he died at age 56, halting the Mongol advance.