Gaucher de Foissy was a client of the House of Guise. The youngest son of a little-known noble family, he became wealthy during his career. Having become one of the Duke’s chief advisers, he served as maître d’hôtel in both the House of Guise and the royal household. Skillful and flexible, he acted more as a noble opportunist than as a Catholic extremist. Thus, during the St. Bartholomew’s Day massacre, he protected a young wealthy Protestant, Françoise de Longuejoue, who married his son. Gaucher married the mother of Charles de Louviers, Lord of Maurevert, and was his guardian during his minority, maintaining relations with him. His brother Bertrand de Foissy, initially a client of the Guises, became close to the king’s brother, Henri d’Anjou, around 1568.