Prince Pierre, Duke of Valentinois

Pierre Grimaldi
Prince Pierre, Duke of Valentinois
Prince Pierre of Monaco, Duke of Valentinois
Born	(1895-10-24)24 October 1895 Château de Kerscamp, Morbihan, France
Died	10 November 1964(1964-11-10) (aged 69) American Hospital, Neuilly-sur-Seine, Paris, France
Burial	Chapel of Peace, Monaco
Spouse	Princess Charlotte, Duchess of Valentinois (m. 1920; div. 1933)
Issue	Princess Antoinette, Baroness of Massy Rainier III, Prince of Monaco
Full name Count Pierre Marie Xavier Raphael Antoine Melchior de Polignac Pierre Grimaldi de Polignac
House	Polignac (by birth) Grimaldi (by marriage)
Father	Count Maxence de Polignac
Mother	Susana de la Torre y Mier

Prince Pierre of Monaco, Duke of Valentinois (French: Duc de Valentinois; 24 October 1895 – 10 November 1964) was the father of Rainier III of Monaco. He was a promoter of art, music, and literature in Monaco and served as the head of the country's delegation to the United Nations Educational, Scientific, and Cultural Organization (UNESCO) and to the International Olympic Committee.

Born at the Château de Kerscamp, Hennebont, Morbihan, France, as Count Pierre Marie Xavier Raphael Antoine Melchior de Polignac, he was the fourth son and youngest child of Count Maxence Melchior Edouard Marie Louis de Polignac (1857–1936) and his Mexican-born wife whom he wed in Paris in 1881, Susana Mariana Estefanía Francisca de Paula del Corazón de la Torre y Mier y Teran (1858–1913). He was a first cousin twice removed of major-general Camille Armand Jules Marie, Prince de Polignac and nephew of the Mexican politician .

He married civilly on 19 March and religiously on 20 March 1920 in Monaco, Princess Charlotte of Monaco, the illegitimate but adopted daughter of Louis II of Monaco by Marie Juliette Louvet. Pierre de Polignac, member of a cadet branch of one of France's most renowned ducal families, noble at least since the 12th century, duke in 1780, peer in 1817, and a descendant of Marie Antoinette's favourite, Yolande de Polatron, duchesse de Polignac), he changed his name and coat of arms to those borne by the House of Grimaldi by Monegasque ordinance issued on 18 March 1920, the day before his wedding. He had become a subject of the Sovereign Prince of Monaco, also by Monegasque ordinance, on 29 February 1920. From the date of the religious wedding the court of Monaco referred to him, jure uxoris, as Duke of Valentinois. That title had been conferred upon his wife as heiress presumptive on 20 May 1919. His surname and arms were altered by Monegasque ordinance shortly after he became a Monegasque citizen to ensure that his dynastic issue would bear the surname of Grimaldi in compliance with Article I of Monaco's house law). Pierre remained in succession to the French title Duke of Polignac, as do his legitimate male-line descendants.