Niccolò Machiavelli was a diplomat and official of the Florentine republic. Removed from power when the Medici returned, he wrote The Prince, a manual on how to win and keep power. For describing politics as it is, and not as it should be, he was called cynical, but also the founder of modern political science.
Core ideas
Politics has its own rules, separate from religious and private morality
The ideal ruler is both feared and loved, but if he cannot be both, it is better to be feared
Fortune governs half of events, and the leader's virtue decides the rest
The tradition: Political realist
A political realist analyzes power as it actually works, without moral idealization. Machiavelli is the great founder of this way of thinking about politics.