Decretum Gratiani in the context of Jurisprudence of Catholic canon law

The 1917 Code of Canon Law (abbreviated 1917 CIC, from its Latin title Codex Iuris Canonici), also referred to as the Pio-Benedictine Code, is 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).

From the 5th century to the 7th century AD, about thirty synods, variously counted, were held at Toledo (Concilia toletana) in what would come to be part of Spain. The earliest, directed against Priscillianism, assembled in 400. The "third" synod of 589 marked the epoch-making conversion of King Reccared from Arianism to Catholic Chalcedonian Christianity. The "fourth", in 633, probably under the presidency of the noted Isidore of Seville, regulated many matters of discipline and decreed uniformity of liturgy throughout the kingdom. The Britonia of Galicia accepted the Latin liturgical rite. The "twelfth" council in 681 assured to the archbishop of Toledo the primacy of Hispania (present Iberian Peninsula). As nearly one hundred early canons of Toledo found a place in the Decretum Gratiani, they exerted an important influence on the development of ecclesiastical law.

The later synod of 1565 and 1566 concerned itself with the execution of the decrees of Trent; and the last council of Toledo, that of 1582 and 1583, was so guided in detail by Philip II that the pope ordered the name of the royal commissioner to be expunged from the acts.

The Decretals of Gregory IX (Latin: Decretales Gregorii IX), also collectively called the Liber extra, are a source of medieval Catholic canon law. In 1230, Pope Gregory IX ordered his chaplain and confessor, Raymond of Penyafort, a Dominican, to form a new canonical collection destined to replace the Decretum Gratiani, which was the chief collection of legal writings for the church for over 90 years. It has been said that the pope used these letters to emphasize his power over the Universal Church.

The jurisprudence of Catholic canon law is the complex of legal theory, traditions, and interpretative principles of Catholic canon law. In the Latin Church, the jurisprudence of canon law was founded by Gratian in the 1140s with his Decretum. In the Eastern Catholic canon law of the Eastern Catholic Churches, Photios holds a place similar to that of Gratian for the West.

Much of the legislative style was adapted from that of Roman law, especially the Justinianic Corpus Juris Civilis. As a result, Roman ecclesiastical courts tend to follow the Roman law style of continental Europe with some variation. After the fall of the Roman Empire and up until the revival of Roman law in the 11th century, canon law served as the most important unifying force among the local systems in the civil law tradition. The canonists introduced into post-Roman Europe the concept of a higher law of ultimate justice, over and above the momentary law of the state.