Rainier III, Prince of Monaco Rainier III, Prince of Monaco Rainier III (Rainier Louis Henri Maxence Bertrand Grimaldi; 31 May 1923 – 6 April 2005) ruled the Principality of Monaco for almost 56 years, making him one of the longest ruling monarchs in European history. Though internationally known for his marriage to American actress Grace Kelly, he was also responsible for reforms to Monaco's constitution and for expanding the principality's economy beyond its traditional casino gambling base. Gambling accounts for only approximately three percent of the nation's annual revenue today; when Rainier ascended the throne in 1949, it accounted for more than 95 percent. Rainier
Honoré III, Prince of Monaco of Maria Clementina Sobieski. The marriage never materialised and as such, in 1751, he married Maria Caterina Brignole (d. 1813). The couple had two children; Honoré IV, Prince of Monaco and Joseph Grimaldi (10 September 1763 – 28 June 1816) before divorcing in 1770, and Marie-Catherine married the Prince de Condé in 1798. Honoré III, Prince of Monaco Prince Honoré III, Prince of Monaco (10 November 1720 – 21 March 1795) ruled as Prince of Monaco and was Duke of Valentinois from 1731 to 1793. Honoré was the son of Louise Hippolyte, Princess of Monaco and her husband Prince Jacques.