Vatican City was brought into being by a treaty.
Vatican City . The independent city-state , on the other hand , came into existence in 1929 by the Lateran Treaty between the Holy See and Italy , which spoke of it as a new creation , not as a vestige of the much larger Papal States ( 756 -- 1870 ) , which had previously encompassed much of central Italy . According to the terms of the treaty , the Holy See has `` full ownership , exclusive dominion , and sovereign authority and jurisdiction '' over the city-state .