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
Prince Ernst August of Hanover (born 1954) retain her claim to the throne of Monaco and to transmit succession rights to future offspring, the couple were also obliged to obtain the approval of yet a third nation, in the form of official consent to the marriage of Caroline's father, Prince Rainier III as the sovereign of Monaco. Nonetheless, Caroline was a Roman Catholic and Ernst August the heir male of George III when the couple wed, at which time a provision of the Act of Settlement 1701 stipulated that in the event the British crown is to devolve upon an heir married to "a Papist", that heir