Vatican City was established as a city-state by the Lateran Treaty.
 But the Popes did not recognize 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 (18461878), the last ruler of the Papal States, was referred to as a "prisoner in the Vatican"
The most famous Lateran buildings are the Lateran Palace, once called the Palace of the Popes, and the Archbasilica of Saint John Lateran, the cathedral of Rome, which although part of Italy is a property of the Holy See, which has extraterritorial privileges as a result of the 1929 Lateran Treaty

