The Mongols after Genghis Khan

The death of Genghis Khan did not end Mongol expansion — it redirected it. The decades after his death saw the empire reach its greatest territorial extent, but also saw the first serious cracks in its unity. The story of this period is really the story of two forces pulling in opposite directions: the momentum of conquest, and the internal politics of succession within the ruling family.

Mongol expansion after Genghis Khan can be divided into two distinct phases. The first, spanning the years 1236–42, brought major gains in the Russian steppes, including the conquest of Bulghar, Kiev, Poland and Hungary. The second phase, covering 1255–1300, saw the conquest of all of China by 1279, along with Iran, Iraq and Syria. After these campaigns, the frontier of the empire stabilised.

In the decades after 1203, Mongol military forces met with very few reversals. But noticeably, after the 1260s, the original impetus of campaigns could not be sustained in the West. Vienna, and beyond it western Europe, as well as Egypt, were within the grasp of Mongol forces — yet the Mongols retreated from the Hungarian steppes and were defeated by Egyptian forces. These two events signalled the emergence of new political trends.

There were two facets to this shift. The first was a consequence of internal politics of succession within the Mongol family. In the first two generations after Genghis Khan, the descendants of Jochi and Ogodei allied to control the office of the Great Khan. These interests mattered more to them than pursuing campaigns in Europe. The second compulsion occurred as the Jochi and Ogodei lineages were marginalised by the Toluyid branch of Genghis Khanid descendants.

With the accession of Mongke, a descendant of Toluy — Genghis Khan's youngest son — military campaigns were pursued energetically in Iran during the 1250s. But as Toluyid interests in the conquest of China increased during the 1260s, forces and supplies were increasingly diverted into the heartlands of the Mongol dominion. As a result, the Mongols fielded a small, understaffed force against the Egyptian military. Their defeat, combined with the growing preoccupation of the Toluyid family with China, marked the end of western expansion of the Mongols.

Concurrently, conflict between the Jochid and Toluyid descendants along the Russian-Iranian frontier diverted the Jochids away from further European campaigns. …