Apostolic vicariate in the context of "List of Catholic dioceses (structured view)"

An apostolic prefect or prefect apostolic is a priest who heads what is known as an apostolic prefecture, a 'pre-diocesan' missionary jurisdiction where the Catholic Church is not yet sufficiently developed to have it made a diocese. Although it usually has an (embryonal) see, it is often not called after such city but rather after a natural feature, or administrative geographical area, which may be a name in use by the local inhabitants, or one assigned by a colonial authority, depending on the circumstances under which the prefecture was established.

If a prefecture grows and flourishes, it may be elevated to an apostolic vicariate, headed by a titular bishop, in the hope that with time the region will generate enough Catholics and stability for its Catholic institutions, to warrant being established as a diocese. Both these stages remain missionary, hence exempt, that is, directly subject to the Holy See, specifically the Dicastery for Evangelization, rather than, as a diocese normally would, belong to an ecclesiastical province.

A military ordinariate is an ecclesiastical jurisdiction of the Catholic Church, of the Latin or an Eastern church, responsible for the pastoral care of Catholics serving in the armed forces of a nation.

Until 1986, they were called "military vicariates" and had a status similar to that of apostolic vicariates, which are headed by a bishop who receives his authority by delegation from the Pope. The apostolic constitution Spirituali militum curae of 21 April 1986 raised their status, declaring that the bishop who heads one of them is an "ordinary", holding authority by virtue of his office, and not by delegation from another person in authority. It likened the military vicariates to dioceses. Each of them is headed by a bishop, who may have the personal rank of archbishop. If the bishop is a diocesan, he is likely to delegate the daily functions to an auxiliary bishop or a lower cleric.

A territorial prelate is, in Catholic usage, a prelate whose geographic jurisdiction, called territorial prelature, generally does not belong to any diocese and is considered a particular church.

The term is also used in a generic sense, and may then equally refer to an apostolic prefecture, an apostolic vicariate, a permanent apostolic administration (which are pre-diocesan, often missionary, or temporary), or a territorial abbacy (see there).

In the canon law of the Catholic Church, a mission sui iuris (Latin: missio sui iuris, pl. missiones sui iuris), also known as an independent mission, can be defined as: "an ecclesial structure erected from a previous territory, with explicit boundaries, under the care of a religious community or other diocese, responding to a missionary exigency and headed by a superior nominated by the Holy See, under the aegis of the Congregation for the Evangelization of Peoples."

It is generally applied to an area with very few Catholics, or in areas where Christianity (in particular Roman Catholicism) is either outlawed or undergoing persecution, often desolate or remote, and ranks below an apostolic prefecture and an apostolic vicariate.

Bishop Stephen Peter Alencastre, SSCC (born Estêvão Pedro de Alencastre; November 3, 1876 – November 9, 1940) was a bishop of the Roman Catholic Church who served as the fifth and last Vicar Apostolic of the Vicariate Apostolic of the Hawaiian Islands (now the Diocese of Honolulu). He was also an apparent titular bishop of Arabissus.

Missionary work of the Catholic Church has often been undertaken outside the geographically defined parishes and dioceses by religious orders who have people and material resources to spare, and some of which specialized in missions. Eventually, parishes and dioceses would be organized worldwide, often after an intermediate phase as an apostolic prefecture or apostolic vicariate. Catholic mission has predominantly been carried out by the Latin Church in practice.

In the Roman Curia, missionary work is organised by the Dicastery for Evangelisation.