Vatican City, officially the Vatican City State, is the Holy See's independent city state, an enclave within Rome, Italy. The Vatican City State, also known as The Vatican, became independent from Italy with the Lateran Treaty, and it is a distinct territory under "full ownership, exclusive dominion, and sovereign authority and jurisdiction" of the Holy See, itself a sovereign entity of international law, which maintains the city state's temporal, diplomatic, and spiritual independence. With an area of 49 hectares and a population of about 825, it is the smallest state in the world by both area and population. As governed by the Holy See, the Vatican City State is an ecclesiastical or sacerdotal-monarchical state ruled by the pope who is the bishop of Rome and head of the Catholic Church. The highest state functionaries are all Catholic clergy of various national origins. After the Avignon Papacy, the popes have mainly resided at the Apostolic Palace within what is now Vatican City, although at times residing instead in the Quirinal Palace in Rome or elsewhere.