PLS HELP IK IT'S A TEST BUT IDK HOW TO DO THIS OR UNDERSTAND IT AND ALSO ADD MY S MEMPHISCRA20

I don't know how to put this: I'm not sure how to say this in the clearest or most accurate way sorry

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.

i think it was   tsar alexander ii