An apostolic administrator in the Roman Catholic Church is a prelate appointed by the Pope to serve as the ordinary for an apostolic administration. An apostolic administration can either be an area that is not yet a diocese (a stable 'pre-diocesan', usually missionary apostolic administration) or for a diocese, eparchy or similar permanent ordinariate (such a a territorial prelature or a territoriall abbacy) that either has no bishop (an apostolic administrator sede vacante, as after an episcopal death or resignation) or, in very rare cases, has an incapacitated bishop (apostolic administrator sede plena).