plenipotentiary

täysivaltainen edustaja A person invested with full powers, especially as the diplomatic agent of a sovereign state, (originally) charged with handling a certain matter
1937, w:P._G._Wodehouse P. G. Wodehouse, w:Lord_Emsworth_and_Others|'Lord Emsworth and Others', Overlook, Woodstock: 2002, p 232.

Meeting him in the street and ignoring the foul bowler hat he wore on his walks abroad, you would have put him down as a Bishop in mufti or, at the least, a plenipotentiary at one of the better courts.

Two of them are hanging up there on Golgotha, and that ought to be enough to show the authority of Rome’s ah plenipotentiary.