Niccolò Machiavelli was born in Florence in 1469 and died in 1527. Machiavelli's father was a lawyer, so his son received a good education and became a secretary for the city of Florence.
Machiavelli was a diplomat, general, and a writer. He is best remembered for writing two books: The Prince, and The Discourses. In these two books, he says that it is impossible to be a good politician and a morally good person.
In Machiavelli's view, a good prince (king, president, etc.) had one important role: to protect the city (or country) that he was governing from external and internal threats. He had to know how to fight, but also had to care about his reputation for the people he was governing.
In other words, the people should not think he was soft, or easy to disobey, but not cruel enough to disgust them. He should seem strict but reasonable.
In Machiavelli's view, it would be great if the leader would be both loved and respected by his people, but if he would have to choose, a severe leader would be better because he would be able to easier control the population.