When machiavelli wrote the prince in 1513 he faced a lot of criticism what were the key ideals of the prince and how did these ideas influence european rulers

The key ideas of "The Prince" were about power and how leaders specifically princes could seek to gain power and also how they could go about maintaining power. These ideas helped to influence European rulers and individuals around the world by promoting this particular type of leadership and power seeking. 

monarchy doesn’t have to have the hereditary element. there have been elective monarchies in the past where you choose your king-for-life and when he dies elect someone else for the job.