When we last left Italy it was after the unification of the various Italian states into one new nation-state and the Pope was sulking in the Vatican, refusing to recognize the new Italian government and declaring that any Italian citizens who participated with the new government were automatically to be excommunicated. This actually presented a problem for Italy in that it created a spiritual/philosophical crisis for the new nation, on the one hand Italian liberals sought to separate the new nation-state of Italy from the influence of the Catholic Church but for many Italians the Church was a central pillar of their life. This standoff made it more difficult for the Italian government to build a strong support-base among some segments of its governed population and also presented a problem with its own leadership, some in control of the new Italian nation-state felt it fine that the Pope wanted to sulk in the Vatican, they would rather have Italians with divided consciousness on the matter of their citizenship and place in the world than bow to the demands of the Catholic Church. This impasse remained in place until the rise of a new form of government in Italy in 1922 with Mussolini’s “triumphant march” on Rome and his being asked to form a new government by Italy’s King – a Fascist government – the first such manifestation of this new method of political organization.
Mussolini spent several years consolidating his hold on power in Italy but the continual problem of the political conflict with the Catholic Church was a concern for Mussolini, he wanted Italians able to freely link themselves to his new Fascist state and to achieve this goal he felt he needed the backing of the Church. In 1926 Mussolini’s government began negotiating with the Holy Pontiff to come to an agreement on the status of Vatican City, the Papacy, and the integration of Rome formally into Italy in a manner recognized by the Catholic Church and the Italian government. On 11 February 1929 this treaty was concluded, the Lateran Treaty, signed by Mussolini acting on behalf of the Italian King and by the Vatican’s secretary of state, Cardinal Pietro Gasparri. The treaty was a critical component in increasing the power of the Fascist state in Italy, it allowed Mussolini to tap into the emotional and psychological power of the Catholic Church, which now formally supported the new state and allowed priests to speak out in its favor in churches throughout Italy. It also critically removed some pious Italians’ concerns about balancing service to the new Italian national government against their faith and loyalty to the Catholic Church. In exchange the Papacy got Vatican City declared a sovereign nation, a cash settlement for the loss of its former Roman holdings, and also the declaration that Catholicism was the only religion of the Italian state. (This aspect of the treaty remained in legal force until 1984.)
So on a bigger picture what did this treaty mean for history? Well first it is the reason that Vatican City remains a sovereign state even to the present day in the city of Rome, after the fall of Fascist Italy the new Italian government slapped that aspect of the treaty into the constitution of the newly reformed Italian nation. Furthermore it pledged that the Pope would remain neutral in international conflicts unless asked to mediate a conflict by all involved parties. But most critically it is one of the major reasons the Papacy remained silent throughout World War II and all the horrific events that occurred during that period. The Lateran Treaty locked the Papacy to the Fascist state and, despite minor efforts by the Papacy to oppose what was happening, the treaty and the demands of realpolitik kept the Papacy silent during World War II.
The Lateran Treaty also happened to finally formally put to rest the issues about Rome becoming Italy’s formal capital.