Canon Law (Catholic Church) - Early Sources

Early Sources

In the first millennium of the Roman Church, the canons of various ecumenical and local councils were supplemented with decretals of the popes; these were gathered together into collections. In the thirteenth century, the Roman Church began to collect and organize its canon law, which after a millennium of development had become a complex and difficult system of interpretation and cross-referencing. The official collections were the Liber Extra (1234) of Pope Gregory IX, the Liber Sextus (1298) of Boniface VIII and the Clementines (1317), prepared for Clement V but published by John XXII. These were addressed to the universities by papal letters at the beginning of each collection, and these texts became textbooks for aspiring canon lawyers. In 1582 a compilation was made of the Decretum, Extra, the Sext, the Clementines and the Extravagantes (that is, the decretals of the popes from Pope John XXII to Pope Sixtus IV). See Corpus Juris Canonici.

Much of the jurisprudential style was adapted from the Roman Law Code of Justinian. As a result, Roman ecclesiastical courts tend to follow the Roman Law style of continental Europe with some variation, featuring collegiate panels of judges and an investigative form of proceeding, called "inquisitorial", from the Latin "inquirere", to enquire. This is in contrast to the adversarial form of proceeding found in the common law system of English and U.S. law, which features such things as juries and single judges.