Rainier III, Prince of Monaco - Wikipedia
en.wikipedia.org › wiki › Rainier_III,_Prince_of_MonacoRainier III, Prince of Monaco. Rainier III (Rainier Louis Henri Maxence Bertrand Grimaldi; 31 May 1923 – 6 April 2005) was Prince of Monaco from 1949 to his death in 2005. Rainier ruled the Principality of Monaco for almost 56 years, making him one of the longest-ruling monarchs in European history. Rainier was born at the Prince's Palace of Monaco, the only son of Prince Pierre and Hereditary Princess Charlotte of Monaco.