Pope Benedict XV promulgates the 1917 Code of Canon Law, the first comprehensive codification of Catholic canon law in the legal history of the Catholic Church.

The 1917 Code of Canon Law (abbreviated 1917 CIC, from its Latin title Codex Iuris Canonici), also referred to as the Pio-Benedictine Code, was the first official comprehensive codification of Latin canon law.

Ordered by Pope Pius X in 1904 and carried out by the Commission for the Codification of Canon Law, led by Pietro Cardinal Gasparri, the work to produce the code was completed and promulgated under Pope Benedict XV on 27 May 1917, coming into effect on 19 May 1918. The 1917 Code of Canon Law has been described as "the greatest revolution in canon law since the time of Gratian" (1150s AD).

The 1917 Code of Canon Law remained in force until the 1983 Code of Canon Law took legal effect and abrogated it on 27 November 1983.

Pope Benedict XV (Latin: Benedictus XV; Italian: Benedetto XV), born Giacomo Paolo Giovanni Battista della Chiesa (Italian: [ˈdʒa:komo ˈpa:olo dʒoˈvanni batˈtista della ˈkjɛ:za]; 21 November 1854 – 22 January 1922), was head of the Catholic Church from 1914 until his death in 1922. His pontificate was largely overshadowed by World War I and its political, social, and humanitarian consequences in Europe.

Between 1846 and 1903, the Catholic Church had experienced two of its longest pontificates in history up to that point. Together Pius IX and Leo XIII ruled for a total of 57 years. In 1914, the College of Cardinals chose della Chiesa at the relatively young age of 59 at the outbreak of World War I, which he labeled "the suicide of civilized Europe". The war and its consequences were the main focus of Benedict XV. He immediately declared the neutrality of the Holy See and attempted from that perspective to mediate peace in 1916 and 1917. Both sides rejected his initiatives. German Protestants rejected any "Papal Peace" as insulting. The French politician Georges Clemenceau regarded the Vatican initiative as being anti-French. Having failed with diplomatic initiatives, Benedict XV focused on humanitarian efforts to lessen the impacts of the war, such as attending prisoners of war, the exchange of wounded soldiers and food deliveries to needy populations in Europe. After the war, he repaired the difficult relations with France, which re-established relations with the Vatican in 1921. During his pontificate, relations with Italy improved as well, as Benedict XV now permitted Catholic politicians led by Don Luigi Sturzo to participate in national Italian politics.

In 1917, Benedict XV promulgated the Code of Canon Law, which was released on 27 May, the creation of which he had prepared with Pietro Gasparri and Eugenio Pacelli (future Pope Pius XII) during the pontificate of Pope Pius X. The new Code of Canon Law is considered to have stimulated religious life and activities throughout the Church. He named Pietro Gasparri to be his Cardinal Secretary of State and personally consecrated Nuncio Pacelli on 13 May 1917 as Archbishop. World War I caused great damage to Catholic missions throughout the world. Benedict XV revitalized these activities, asking in Maximum illud for Catholics throughout the world to participate. For that, he has been referred to as the "Pope of Missions". His last concern was the emerging persecution of the Catholic Church in Soviet Russia and the famine there after the revolution. Benedict XV was devoted to the Blessed Virgin Mary and authorized the Feast of Mary, Mediatrix of all Graces.After seven years in office, Pope Benedict XV died on 22 January 1922 after battling pneumonia since the start of that month. He was buried in the grottos of Saint Peter's Basilica. With his diplomatic skills and his openness towards modern society, "he gained respect for himself and the papacy."