What was the main reason the princes of Moscow were able to expand their power and rule Russia?

Question

Quizplus · Accepted Answer

The princes of Moscow expanded their power significantly by cooperating with the Mongols, who ruled over Russia for centuries. This cooperation included serving as tax collectors for the Mongols, which not only ingratiated them with the Mongol rulers but also allowed them to amass wealth and power, setting the stage for the eventual expansion of their rule over Russia.

What Was the Main Reason the Princes of Moscow Were