Al-Farabi was an influential 10th century philosopher born in Transoxania who studied many subjects including philosophy, logic, politics, and mathematics. He proposed theories on human nature, the ideal ruler, and the formation and varieties of states. He described four types of cities - virtuous, ignorance, immoral, and erring - based on their adherence to attaining true happiness for citizens. His political philosophy aimed to advance human societies using some of Plato's approaches while balancing reason and revelation.