Thomas Aquinas wrote about the nature and role of government in On Kingship.
On Kingship was a letter written, as a favor, to king Cyprus. In this letter, Aquinas presents his view on political philosophy. He talks about the role of the government and human nature. Also, Aquinas expresses that the dominion of a tyrant is the worst, but also emphasizes the need of people to to be under an authority. He addresses wether big pieces of land should be ruled by many people or just one. Finally, he also emphasizes the poisonous role of corruption in a society. Also, he recommends king Cyprus to seek God more than vainly honor.