A free city, which is a self-governing urban entity, can be referred to as a city-state, a self-governing city, or a free imperial city. These terms all indicate a city that is independent, often with its own laws and regulations, and is not controlled by a larger governing body. Other synonyms for a free city may include a sovereign city, a liberated city, or an autonomous city. Historically, many European cities were considered free cities, and this idea of independence and self-governance has been an important concept throughout history in various regions of the world.