Founding of the Mongol Empire

Temüjin was proclaimed Genghis Khan at a kurultai. The Mongol Empire became the largest contiguous land empire in history.

In the 12th century the Mongolian plateau was divided among feuding tribes, which the Jin dynasty kept in check by setting them against one another. Temüjin, who lost his father as a boy, defeated the Keraits, Tatars, Naimans and others in turn to unite the plateau, and in 1206 a kurultai (assembly of chiefs) on the Onon River proclaimed him Genghis Khan.

Genghis Khan broke up the old tribes and reorganised the nomads into military and administrative units of thousands and hundreds (the decimal system), and adopted the Uyghur script to record his laws. With this army he attacked Western Xia and Jin and, to the west, destroyed Khwarazm. After his death (1227) his successors destroyed Jin (1234), conquered Rus’ and raided Eastern Europe (1236–1242) and took Baghdad (1258); Kublai renamed his realm Yuan (1271) and destroyed the Southern Song (1279).

The empire split into the Yuan and the Golden Horde, Chagatai and Ilkhanate khanates, but along roads linked by relay stations (jam) people and goods moved freely in a "Pax Mongolica". Travellers such as Marco Polo crossed between East and West; Islamic astronomy and calendar science reached China, and gunpowder, the compass and printing are thought to have travelled west.

Goryeo faced Mongol invasions from 1231, moved its capital to Ganghwa Island and resisted for nearly thirty years; after making peace it came under Yuan domination.