Administrator (medieval)

A diocesan administrator is a provisional ordinary of a Roman Catholic particular church.

The college of consultors elects an administrator within eight days after the see is known to be vacant. The college must elect as administrator a priest or bishop at least 35 years old. If the college of consultors fails to elect a priest of the required minimum age within the time allotted, the choice of diocesan administrator passes to the metropolitan archbishop or, if the metropolitan see is vacant, to the senior by appointment of the suffragan bishops of the ecclesiastical province.

If a diocese has a coadjutor bishop, the coadjutor succeeds immediately to the episcopal see upon the previous bishop's death or resignation, and there is no vacancy of the see. The see also does not become vacant if the Pope appoints an apostolic administrator.

Before the election of the diocesan administrator of a vacant see, the governance of the see is entrusted, with the powers of a vicar general, to the auxiliary bishop, if there is one, or to the senior among them, if there are several, otherwise to the college of consultors as a whole. The diocesan administrator has greater powers, essentially those of a bishop except for matters excepted by the nature of the matter or expressly by law. Canon law subjects his activity to various legal restrictions and to special supervision by the college of consultors (as for example canons 272 and 485). The diocesan administrator remains in charge until a new bishop takes possession of the see or until he presents his resignation to the college of consultors.

...
Wikipedia