Which person was an italian writer who believed that because people were greedy and self-centered, keeping power by any means was the only way to rule?

Niccolo Machiavelli

Machiavelli was a diplomat in Florence who tried to answer how could a ruler guarantee that he would stay in power by writing The Prince in 1513. Machiavelli claimed that people were greedy and self-centered. He argued that rulers should not be good, and that rulers should do whatever is necessary to keep power and protect their city, including killing and lying. Today, when someone is called a Machiavellian, it means that they are acting tricky and not thinking about the good.

Wait u answered your own question