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
Louis II, Prince of Monaco Honor. In 1908 he returned home, leaving behind his mistress and daughter. At the outbreak of World War I, he re-enlisted in the French Army, proving to be one of the Fifth Army's most outstanding soldiers. He was made a Grand Officer of the Legion of Honor and eventually became a Brigadier General. A political crisis loomed for the Prince because without any other heir, the throne of Monaco would pass to his first cousin Wilhelm, the Duke of Urach, a German nobleman who was a son of Prince Albert's aunt, Princess Florestine of Monaco. To ensure this did not