<P> In 1870, the Pope's holdings were left in an uncertain situation when Rome itself was annexed by the Piedmont - led forces which had united the rest of Italy, after a nominal resistance by the papal forces . Between 1861 and 1929 the status of the Pope was referred to as the "Roman Question". </P> <P> Italy made no attempt to interfere with the Holy See within the Vatican walls . However, it confiscated church property in many places . In 1871 the Quirinal Palace was confiscated by the king of Italy and became the royal palace . Thereafter the popes resided undisturbed within the Vatican walls, and certain papal prerogatives were recognized by the Law of Guarantees, including the right to send and receive ambassadors . But the Popes did not recognise the Italian king's right to rule in Rome, and they refused to leave the Vatican compound until the dispute was resolved in 1929; Pope Pius IX (1846--1878), the last ruler of the Papal States, was referred to as a "prisoner in the Vatican". Forced to give up secular power, the popes focused on spiritual issues . </P> <P> This situation was resolved on 11 February 1929, when the Lateran Treaty between the Holy See and the Kingdom of Italy was signed by Prime Minister and Head of Government Benito Mussolini on behalf of King Victor Emmanuel III and by Cardinal Secretary of State Pietro Gasparri for Pope Pius XI . The treaty, which became effective on 7 June 1929, established the independent state of Vatican City and reaffirmed the special status of Catholicism in Italy . </P> <P> The Holy See, which ruled Vatican City, pursued a policy of neutrality during World War II, under the leadership of Pope Pius XII . Although German troops occupied the city of Rome after the September 1943 Armistice of Cassibile, and the Allies from 1944, they respected Vatican City as neutral territory . One of the main diplomatic priorities of the bishop of Rome was to prevent the bombing of the city; so sensitive was the pontiff that he protested even the British air dropping of pamphlets over Rome, claiming that the few landing within the city - state violated the Vatican's neutrality . The British policy, as expressed in the minutes of a Cabinet meeting, was: "that we should on no account molest the Vatican City, but that our action as regards the rest of Rome would depend upon how far the Italian government observed the rules of war". </P>

When did vatican city become a sovereign state