The Mongols, a pastoral nomadic peoples who lived at the northern borders of China started their military campaigns in the early 13th century under leadership of Genghis Khan or Jenghiz Khan who united the Mongols and Turkic tribes under his authority in 1206. He led series of military campaigns between 1207 and 1227 and set the stage for the creation of the largest empire in history. At Genghis Khan’s death in 1227 the Mongol Empire stretched from the Caspian Sea on the west to the China Sea on the east, and from Siberia on the north to central China on the south.
Genghis Khan’s successor Ogedei Khan (1229-1241) continued the territorial expansion of the Mongol Empire and conquered much of western China and Persia. Batu Khan, son of Jochi and grandson of Genghis Khan who was elected commander of the Mongol army in 1235 conquered whole Russia by 1240. Following the conquest of Russia, Batu Khan invaded Central Europe defeating combined Polish and German forces led by Henry II, Duke of Silesia in the Battle of Legnica on April 9, 1241. Two days later, he decisively defeated the Hungarians led by Bela IV of Hungary in the Battle of Mohi. Despite being victorious Batu Khan withdrew from Central Europe to participate in the election of the great khan in late spring of 1242. The Mongol conquest and invasions in Europe afterwards ceased, while Russia and the territory of today’s Ukraine, Moldova, Kazakhstan and Caucasus were incorporated into the Golden Horde (the western part of the Mongol Empire) for almost two and a half centuries.