Since the annexation of the Kingdom of the Two Sicilies to the newly created Kingdom of Italy in 1861, various attempts by the reigning House of Savoy of Italy to annex the Order were made, but rejected by Pope Pius IX (1846-1878).

Following the death of Francis II, last King of the Two Sicilies, and the succession of his half brother, Prince Alfonso, Count of Caserta, Duke of Castro, and Grand Master from 1892 –1934, the Order continued to enjoy excellent relations with the Papacy. This was particularly so with Pope Pius X and Pope Benedict XV. By Papal Brief of 7 March 1910 Pope Pius X revived the institution of a Cardinal Protector of the Constantinian Order and appointed Cardinal Domenico Ferrata to the post. On his death in 1913, the Pope appointed Cardinal Francesco di Paola Cassetta to replace him. The Secretary of State of the Holy See, Cardinal Rafael Meery del Val, became a Bailiff of the Order in 1912.

Pope Benedict XV (1914-1922) was favourably disposed towards the Constantinian Order and its Roman Catholic tradition and spiritual activity. In 1916 he restored the Church of Sant’Antonio in Naples to the Constantinian Knights, and when Cardinal Cassetta died in 1919 appointed as Cardinal Protector, Cardinal Vittorio Amadeo Ranuzzi de Bianhi to replace him. Pope Benedict’s Secretary of State was also appointed as a Bailiff of the Order at this time.

Pope Benedict also approved the 1919 revision of the Order’s statutes and instructed the Sacred Congregation of Rites to give formal approval, in a Decree of 9 July 1919, to an official calendar of feast days, together with special prayers and Lessons for the Office. The Pope also sanctioned the building of a chapel dedicated to the Constantinian Order in the new basilica of Santa Croce al Flaminio in Rome, which was paid for by the knights.

During the same pontificate the Pope’s new Secretary of State, Cardinal Pietro Gasparri, was invested as a Bailiff on the Constantinian Order, along with numerous other Cardinals including the Archbishops of Baltimore and Boston.