The Vatican City State is a neutral nation, which has not engaged in any war since its formation in 1929 by the Lateran Treaty. It has no formal military compact or agreement with neighbouring Italy, although responsibility for defending the Vatican City from an international aggressor is likely to lie primarily with the Italian Armed Forces. When presenting the Lateran Treaty to the Italian parliament in 1929, Benito Mussolini declared: "It is evident that we [the Italian state] will be the necessary guarantors of this neutrality and inviolability [of Vatican City], since, in the remote hypothesis someone wanted to hurt her, he would first have to violate our territory." Although the Vatican City state has never been at war, it was exposed, together with properties of the Holy See in Rome, to bombings during World War II.

Vatican City, officially the Vatican City State, is a landlocked sovereign country, city-state, microstate, and enclave within Rome, Italy. It became independent from Italy in 1929 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 under international law, which maintains the city-state's temporal power and governance, diplomatic, and spiritual independence. The Vatican is also a metonym for the pope, Holy See, and Roman Curia.