Niccolò Machiavelli was a Renaissance political philosopher known for his work "The Prince," where he argued that effective political leadership often requires manipulation, deceit, and pragmatic realism over morality. He emphasized that the ends can justify the means, advocating for a ruler's strength, cunning, and occasional ruthlessness to maintain power and stability in a state. His ideas have sparked extensive debate about ethics in politics and the balance between morality and efficacy in governance.