In many rites of the Roman Catholic Church and in Anglican churches, a diocese is an administrative territorial unit administered by a bishop. It is also referred to as a bishopric or Episcopal Area (as in United Methodism) or episcopal see, though strictly the term episcopal see refers to the domain of ecclesiastical authority officially held by the bishop. The diocese is the key geographical unit of authority in the form of church governance known as episcopal polity. In the Roman Catholic Church and the Anglican Communion, an important diocese is called an archdiocese (usually due to size, historical significance, or both), which is governed by an Archbishop, who may be exempt from or have Metropolitan authority over the other ('suffragan') dioceses within a wider jurisdiction called an ecclesiastical province. As of 2003, there are approximately 569 Roman Catholic archdioceses and 2014 dioceses. After the Reformation, the Church of England continued and developed the existing diocesan structure in England. This continued throughout the Anglican Communion. In the Eastern Catholic Churches (which recognise papal authority and so are part of the Roman Catholic Church), the equivalent unit is the Eparchy; the Orthodox Church calls its dioceses Metropoleis.

History

See also: Bishops and civil government

In the later organization of the Roman Empire, the increasingly subdivided provinces were administratively associated in a larger unit, the diocese (Latin dioecesis, from the Greek term διοίκησις, meaning "administration").

With the adoption of Christianity as the Empire's official religion in the 4th century, the clergy assumed official positions of authority alongside the civil governors. A formal Church hierarchy was set up, parallel to the civil administration, whose areas of responsibility often coincided. With the collapse of the Western Empire in the 5th century, the bishops in Western Europe assumed a large part of the role of the former Roman governors. A similar, though less pronounced, development occurred in the East, where the Roman administrative apparatus was largely retained by the Byzantine Empire. In modern times, many an ancient diocese, though later divided among several dioceses, has preserved the boundaries of a long-vanished Roman administrative division. For Gaul, Bruce Eagles has observed that "it has long been an academic commonplace in France that the medieval dioceses, and their constituent pagi, were the direct territorial successors of the Roman civitates.

Christian hierarchy

Modern usage of 'diocese' tends to refer to the sphere of a bishop's jurisdiction. This became commonplace during the self-conscious "classicizing" structural evolution of the Carolingian empire in the 9th century, but this usage had itself been evolving from the much earlier parochia ("parish"), dating from the increasingly formalised Christian authority structure in the 4th century (see EB 1911).