The Black Nobility or Black Aristocracy (Italian: "nobiltà nera" or "aristocrazia nera") are Romanaristocratic families who sided with the Papacy under Pope Pius IX after the Savoy family-led army of the Kingdom of Italy entered Rome on September 20, 1870, overthrew the Pope and the Papal States, and took over the Quirinal Palace, and any nobles subsequently ennobled by the Pope prior to the 1929 Lateran Treaty. For the next 59 years, the Pope confined himself to Vatican City and claimed to be a prisoner in the Vatican to avoid the appearance of accepting the authority of the new Italian government and state. Aristocrats who had been ennobled by the Pope and were formerly subjects of the Papal states, including the senior members of the Papal Court, kept the doors of their palaces in Rome closed to mourn the Pope's confinement, which led to their being called the "Black Nobility".
Despite the relatively recent name, the Black Nobility had existed for centuries, originating in the Baronal class of Rome and in the powerful families who moved to Rome to benefit from a family connection to the Vatican. These supported the Popes in the governance of the Papal States and in the administration of the Holy See. Many of the members of Black Noble families also became high-ranking clergy and even Popes. Black Nobility families (in this instance families whose ancestors included Popes) still in existence include notably the Colonna, Massimo, Orsini, Ruspoli, Pallavicini, Borghese, Odescalchi, Schiaratura and Ludovisi. Major extinct papal families include the Savelli, Caetani, the Aldobrandini family and Conti. Famous members of Black Nobility families include Eugenio Pacelli, who later became Pope Pius XII, Ernesto Pacelli, an important financier and Prospero Colonna, mayor of Rome.
Following the conclusion of the Lateran Treaty in 1929, the Black Nobility were given dual citizenship in Italy and Vatican City. Under the provisions of the treaty, noble titles granted by the pope were recognized in the Kingdom of Italy. Many of these families were members of the largely ceremonial Papal Noble Guard; others were foreigners affiliated with the Holy See in various ways. In 1931, Pope Pius XI denied the request of Alfonso XIII of Spain to open the Noble Guard further to nobles from all Catholic countries. In World War II, the Papal Noble Guard guarded the Pope alongside the Swiss Guard.
Pope Paul VI abolished many Vatican City positions with the apostolic letter motu proprioPontificalis Domus (English: The Papal Household) in 1968. As well as changing the name of the group from Papal Court to Papal Household, many of the positions occupied by the Black Nobility were abolished. According to the motu proprio: "Many of the offices entrusted to members of the Papal Household were deprived of their function, continuing to exist as purely honorary positions, without much correspondence to concrete needs of the times." Many of these positions and the Papal Court itself were still set up for administering the Papal States, which had been lost in 1870. The Black Nobility's perks, such as Vatican City licence plates, were also withdrawn. Some Black Nobles resented these changes. In May 1977, some members of the Black Nobility, led by Princess Elvina Pallavicini, started courting traditional Archbishop Marcel Lefebvre.