E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Les Rois Fainéants (the cipher or puppet kings). Clovis II. and his ten successors were the puppet kings of the Palace Mayors. Louis V. (last of the Carlovingian dynasty) received the same designation.
My signet you shall command with all heart, madam, said Earl Philip . I am, you know, a complete Roy Fainéant, and never once interfered with my Maire du Palais in her proceedings.Sir Walter Scott: Peveril of the Peak, chap. xv.