Where did the power of the Holy Roman Emperor come from?

i think the answer will be

Ruling families had allied themselves with the emperor, giving him power.

i am sorry if i am wrong

Here is the answer of the given question above. I will make this answer brief. The power of the Holy Roman Emperor came from a few sources and not just one. First is his ability as a military leader, next is his own standing among the German princes, and of course, the Catholic Church. Hope this is the answer that you are looking for.