In the Roman Curia, a congregation () is a type of department of the Curia. They are second-highest-ranking departments, ranking below the two Secretariats, and above the pontifical councils, pontifical commissions, tribunals and offices. Originally, congregations were select groups of cardinals drawn from the College of Cardinals, commissioned to take care of some field of activity that concerned the Holy See. Today, as a result of a decision of the Second Vatican Council, members include diocesan bishops from diverse parts of the world who are not cardinals. Each congregation also has a permanent staff. Each congregation is led by a Prefect, who is usually a cardinal. Until recently, a non-cardinal appointed to head a congregation was styled pro-prefect until made a cardinal. This practice has been abandoned. History and functioning Certain curial departments have been organized by the Holy See at various times to assist it in the transaction of those affairs which canonical discipline and the individual interests of the faithful bring to Rome. Among the most important were the Roman Congregations, traditionally comprising cardinals who assist the pope in the administration of the affairs of the Church. Under the current law, the dicasteries are juridically equal, but congregations generally have more direct jurisdiction than other dicasteries. The Roman Congregations originated from the necessity, felt from the beginning, of studying the questions submitted for pontifical decision, in order to sift the legal questions arising and to establish matters of fact. Ecclesiastical business used to be handled by the pontifical chancery. This work, at first entrusted to the papal chaplains, was afterwards divided between the penitentiarii and the auditores, according as questions of the internal or the external forum (i.e., jurisdiction) were to be considered. Thereafter, cardinals in greater or less number were associated with them. Often, however, they were not merely entrusted with the preparation of the case, but were given authority to decide it. However, the ever-growing number of business items and the ever-increasing complexity of the issues necessitated the creation of separate, specialised administrative-legislative bodies (the administrative and legislative functions of ecclesiastical government are not as sharply separated in the Catholic Church as in a secular government with the separation of powers). Pope Sixtus V was the first to distribute this administrative business among different congregations of cardinals; and in his Apostolic Constitution Immensa Aeterni Dei (22 January 1588) he generalized the idea, already conceived and partly