How did the Khans of the Golden Horde rule over the Ruussian city-states?

The campaign was heralded by the Battle of the Kalka River in May 1223, which resulted in a Mongol victory over the forces of several Rus' principalities. ... All Rus' principalities were forced to submit to Mongol rule and became vassals of the Golden Horde empire, some of which lasted until 1480

Explanation:

the mongolian invasion of china and central asia resulted in a disruption of the silk road as the chinese garrisons lost support from the chinese kingdoms which fell under the mongols. however, as the mongols established a formal dynasty in china, the successors of genghis khan restored the garrisons along the silk road allowing the safe travel caravans again.

wait history, who want to talk about history, boring.