"The prince" was the first book that didn't take politics as something ethical or philosophical. Machiavelli wrote it to Lorenzo di Medici as a "guide" to maintain his power. Ancient philosophers were focused on constucting the ideal state. That means, they mentioned the characteristics of a succesfull monarchy for example, but did not considered the things as they were at that moment. Readers find disturbing the tactics that Machiavelli describes to gain or maintain power as they include making people fear you or destroying your enemies. This book is always resumed with the phrase "The end justifies the means", making it clear that the rulers can do anything to maintain their power.
The controversy is understandable, this books shows how cruel can reality be and how politics scrifice ethics in the name of power. The discussion is still relevant nowadays. How far can politicians go to win an election?
