|  | 
Definition of Duchesse de Valentinois
1. Noun. French noblewoman who was the mistress of Henry II; she had more influence over him than did his wife Catherine de Medicis (1499-1566). 
|  | 
1. Noun. French noblewoman who was the mistress of Henry II; she had more influence over him than did his wife Catherine de Medicis (1499-1566).