Vatican City i/ˈvætɨkən ˈsɪti/, or Vatican City State, in Italian officially Stato della Città del Vaticano (pronounced [ˈstaːto della t͡ʃitˈta del vatiˈkaːno]), is a landlocked sovereign city-state whose territory consists of a walled enclave within the city of Rome, Italy. It has an area of approximately 44 hectares (110 acres), and a population of just over 800. This makes Vatican City the smallest internationally recognized independent state in the world by both area and population. The Pope is also the Head of State and Government of the Vatican City State.
Vatican City was established as an independent state in 1929 by the Lateran Treaty, signed by Cardinal Secretary of State Pietro Gasparri, on behalf of Pope Pius XI and by Prime Minister Benito Mussolini on behalf of King Victor Emmanuel III of Italy. The treaty spoke of it as a new creation (Preamble and Article III), not as a vestige of the much larger Papal States (756–1870) that had previously encompassed much of central Italy. Vatican City State is distinct from the Holy See
More information on the Wikipedia page