Lateran Treaty
Negotiations for the settlement of the Roman Question began in 1926 between the government of Italy and the Holy See, and culminated in the agreements of the Lateran Pacts, signed—the Treaty says—for King Victor Emmanuel III of Italy by Benito Mussolini, Prime Minister and Head of Government, and for Pope Pius XI by Pietro Gasparri, Cardinal Secretary of State, on 11 February 1929. It was ratified on 7 June 1929. The agreements were signed in the Lateran Palace, hence the name by which they are known.
Vatican lira
The Papal States, by then reduced to a smaller area close to Rome, used its own lira between 1866 and 1870, after which it ceased to exist. In 1929, the Lateran Treaty established the State of the Vatican City and, according with the terms of the Treaty, a distinct coinage was introduced, denominated in centesimi and lire, on par with the Italian lira. Italian coins and banknotes were legal tender in the Vatican City. The Vatican coins were minted in Rome and were also legal tender in Italy and San Marino.