A nominal subordinate wielding the power of his titular superior. Now historical.
Originating in the Frankish kingdoms under the later Merovingian kings; hence also Mayor of Austrasia, Mayor of Neustria..
Origin
Mid 16th century; earliest use found in John Rastell. After post-classical Latin major palatii and, in later use, Middle French, French maire du palais; compare post-classical Latin majores palatii palace dignitaries, and major-domo.