Following the occupation of Rome in 1870, relations with the papacy became the major concern of the Italian government. Pope Pius IX was determined to maintain control of at least a symbolic portion of the city. This no Italian government would allow, for fear of foreign involvement (Pius asked Prussia to intervene on his behalf in the summer of 1870). A generous settlement was necessary. In May 1871, the Italian state unilaterally recognized the pope as a head of state, conceded his right to free communication with foreign Catholics, gave diplomatic recognition to foreign ambassadors at the Vatican, and offered a substantial annual subsidy (later refused) for the papal court’s expenses. The government also renounced some of its powers over the nomination of bishops within Italian territorial boundaries, although it was prevented from abolishing all jurisdiction over Church affairs by the strongly anticlerical majority in Parliament.
These guarentigie (guarantees) were greeted with hostility by Pius IX. For the next 50 years, Pius IX and his successors treated themselves as prisoners of conscience and refused to go outside the walls of St. Peter’s. Pius also unsuccessfully attempted to persuade the Catholic nations of Europe to maintain their embassies at Florence, the former capital, not Rome. A papal ban forbidding Catholic heads of state to visit Rome was enacted and remained in force until 1920. Pius’s reaction was not mere pique. The pope could not afford to bow to the law for fear that foreign countries would use his subordination to the Italian state as an excuse to interfere with his spiritual powers over their Catholic citizens. Even without the pope’s participation, however, the guarantees provided a modus vivendi between church and state until they were superseded by the Lateran pacts in 1929.
Historical Dictionary of Modern Italy. Mark F. Gilbert & K. Robert Nilsson. 2007.