APOSTOLIC PREFECTURE AND APOSTOLIC PREFECT. — An apostolic prefecture is an ecclesiastical territory with defined boundaries, not erected as a diocese, governed by an apostolic prefect. Together with the apostolic vicariate (q.v.) and the autonomous mission or *sui iuris* mission, it forms part of the territorial missionary organization, also called a quasi-diocese, which is normally directly dependent on the Apostolic See.
The juridical evolution of this institution has not yet been sufficiently clarified. Among the Eastern Churches, as can be gathered from the *motu proprio* *Auspicia rerum* of Leo XIII, 19 March 1896, and from the decree of the Sacred Congregation of Propaganda Fide, *Excelsum*, 12 September 1896, there existed apostolic prefectures without their own territory within the limits of another mission or diocese; among the Latin Churches it is certain that there were apostolic prefectures with their own separate territory, juridically independent at least by the mid-19th century. The institution was already firmly defined by the end of the 19th century. In the preparatory schemas of the *Codex Iuris Canonici*, the apostolic prefecture appears in perfect parity with the apostolic vicariate, as it was later incorporated into the same *Codex*.
The erection of an apostolic prefecture is reserved to the supreme ecclesiastical authority, and its territorial boundaries are not subject to prescription. It is usually divided into missionary stations, quasi-parishes, and missionary districts; generally it is a completely independent territory, though in practice it may be included within a province of missionary or common law and thus, in accordance with the *Codex Iuris Canonici*, subject to the jurisdiction of the metropolitan. The internal administration follows that of a diocese: the quasi-diocesan curia is composed of the titular, a delegate vicar with powers similar to those of a vicar general, and a Mission Council which performs the functions of a cathedral chapter, though with different modalities. The internal administration (during a vacant or impeded see) is assumed by the pro-prefect, acting almost as a vicar capitular, appointed by the apostolic prefect himself.
When the progress of evangelization becomes consolidated, the apostolic prefecture is elevated to the rank of apostolic vicariate.