How did so few Mongols rule so many people?

The short answer

• Steppe practices on a larger scale. The Mongols adapted familiar steppe practices to an empire containing agricultural societies. Changing horses along a route became the yam; census rolls extended the decimal army's muster lists; and the paiza enlarged the use of a chief's safe-conduct token. Scale also required skills from conquered peoples. Khitan clerks, Uyghur scribes, Persian tax farmers and Chinese engineers filled different roles, and the Uyghur alphabet supplied a script for Mongol.
• Religious communities and the court. The court allowed religious communities room to operate under the khan's authority. Exempting clergy from taxes gave them an interest in Mongol peace, and prayers for the khan acknowledged the power that protected them. Rubruck described a Christian–Muslim–Buddhist debate at court; he admitted that his own side fared poorly once the drinking began. The encounter shows both the variety present at court and the imperial setting in which it met.
• The memory of conquest. The census taker did not arrive in a city untouched by the army. Massacres had shown what resistance could bring, and fear had already persuaded other cities to open their gates to Genghis. A demand for cooperation carried that history with it. The Mongols could use fewer garrisons partly because the threat behind their officials was credible.

What it changed

Routes and exchange. Imperial authority over routes, backed by the census, yam and paiza, helped bring much of the Silk Road under one jurisdiction. Stations supplied travelers whose authority could be recognized along the way. Chapter 12 follows other movement made possible by connected routes: the Polos' journey, the spread of technologies and the pathogen that followed.

Clients use imperial support. Local rulers could use the empire for their own purposes. Rus princes, Seljuk sultans and Korean kings competed to be useful to khans who could support their succession claims. Moscow later rose as a chief tax collector, while the Goryeo royal family survived through marriage ties with the Mongols. Imperial rule endured partly because such clients could see advantages in it.

A prize for rival branches. Möngke's audits drew authority toward the center even as the family's branches put down regional roots: Jochids on the Volga and Toluids in China and Persia. When he died at Diaoyu, his brothers were campaigning in Syria and China. The centralized system offered no procedure for two centers of authority, and control of its machinery became a prize in the succession struggle.