Duke of Valentinois in the context of "Jacques I, Prince of Monaco"

The House of Grimaldi is the reigning house of the Principality of Monaco. The house was founded in 1160 by Grimaldo Canella in Genoa and became the ruling house of Monaco when Francesco Grimaldi captured Monaco in 1297.

Every Prince of Monaco has been a member of the House of Grimaldi. Since the 18th century, the princes have been agnatic descendants of other families that have inherited through the female line and adopted the Grimaldi name. In 1715, Jacques Goyon de Matignon married Louise Hippolyte, Princess of Monaco, the last Grimaldi agnatic heir. He and his male line descendants, adopting the Grimaldi name, ruled as princes of Monaco from 1731 to 1949. During much of the Ancien Régime, the family resided in the French court, where from 1642 to 1715, they used the title of Duke of Valentinois.

Honoré IV (Honoré Charles Anne Grimaldi; 17 May 1758 – 16 February 1819) was Prince of Monaco and Duke of Valentinois from 1814 to 16 February 1819. Because of his illness, the state of affairs was managed by a regency of his brother Joseph Grimaldi and his son Prince Honoré V.

Charles III (Charles Honoré Grimaldi; 8 December 1818 – 10 September 1889) was Prince of Monaco and Duke of Valentinois from 20 June 1856 to his death. He was the founder of the famous casino in Monte Carlo, as his name in Monegasque and Italian was Carlo III. He was born in Paris, the only son of Florestan, Prince of Monaco, and Caroline Gibert de Lametz.