Suggestion for High renaissance topic?

I have to write a research paper on the High Renaissance. I want to write it on Michelangelo, Leonardo and Raphael. But i am having a hard time figuring out what to write about them. I was trying to find something they have in common besides art. I am thinking it’s the rivalry and competition for patrons that they have in common. But I would like to know if there was more than competition that they had in common with one another. Any suggestions?