custos regni

plural custodes regni

1. A kind of viceregal locum tenens appointed, either alone or jointly, to execute the political duties of a monarch during his or her absence from the seat of government.

   If the King be abſent, and taken captive, the People may give the Royall power to one, or to ſome few to exerciſe it as cuſtodes regni.

   1644 October 7, Samuel Rutherford, Lex, Rex: The Law and the Prince, page 148

   1 more example

   It was reſolved…[to] Petition…His Majeſty, to appoint a Cuſtos Regni, or Locum tenens during his Abſence out of this Kingdom; and amongſt other things, in ſpecial to give him Power, to give the Royal Aſſent in Parliament, and to do ſuch things as the King might do if he were preſent. [It was] reſolved…that His Majeſty be likewiſe Petitioned, That an Act of Parliament may paſs to this Effect, That ſuch Commiſſion ſhall not be repealed, until His Majesties return from Scotland to the City of London or Weſtminſter, or be preſent in full Parliament.

   1683, John Nalson, An Impartial Collection of the Great Affairs of State, II, page 412