Monegasque royalty, ruler of the Monaco principality of 370 acres, which under the terms of the Treaty of 1918 with France, will fall under French rule if the royal family dies out. He ascended to the throne on 9 May 1949 and reigned until his death on 6 April 2005.
His marriage with Grace Kelly on 18 April 1956 produced a son Albert (who succeeded him as Albert II), and two daughters, Caroline and Stephanie. His son’s failure to marry and produce an heir prompted Rainier to change the law of succession to include Albert’s nephews, thus ensuring the royal continuation. Prince Rainier was widowed on 14 September 1982 when his wife, Grace Kelly, had a fatal car accident. He never remarried.
In February 2004, the Prince was hospitalized with a coronary lesion and a damaged blood vessel. Just the month before, he had spent three weeks for fatigue. In failing health, he was again hospitalized on 7 March 2005 for a bronchial-pulmonary infection. Two weeks later on 22 March 2005 he was admitted to the intensive care unit.
The principality’s beloved monarch died in a Monaco hospital at age 81 on 6 April 2005 at 6:35 AM local time. His death was attributed to the heart, kidney and respiratory problems that had caused him to be hospitalized in the several weeks leading up to his death. He was credited with having good business sense, vision and leadership skills that led Monaco to develop from a tiny principality where gamblers could visit into a successful and wealthy place attractive to residents and tourists alike. He was succeeded by his only son, who became Prince Albert II.
Link to Wikipedia biography