What made Genghis Khan and his army successful?

When people talk about why Mongol Empire didn’t conquer more, they give different reasons, such as infighting between the successors of Chinggis khan, they fought one type of warfare, Western Europe was heavily fortified etc. But the explanation is actually quite simple. Chinggis Khan above all was a nomad and he knew how to look after his livestock. A typical campaign wouldn’t start unless the horses were…