. . "An apostolic prefect or prefect apostolic is a priest who heads what is known as an apostolic prefecture, a missionary area where the Catholic Church is not yet sufficiently developed to have it made a diocese.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.The usual sequence of development is: mission, prefecture, vicariate, diocese.The apostolic prefecture and the apostolic vicariate are to be distinguished from the territorial abbacy (formerly called an \"abbey nullius\")."@en .