Prince Rainier III, also known as Rainier Louis Henri Maxence Bertrand Grimaldi was the ruler of Monaco for nearly 56 years. He was one of the longest reigning monarchs in European history. Prince Rainier Grimaldi was born in Monte Carlo, Monaco and his parents got divorced when he was a child. He stayed with his mother who was the only child of Louis II of Monaco and the sole successor to the Monegasque throne. After studying in the finest schools of England and Switzerland, he went on to complete his graduation from France and also served during the World War II, fighting against the Nazi occupation. Subsequently, his mother renounced her right to become the princess and after his grandfather’s death, he was crowned as His Serene Highness Rainier III, Sovereign Prince of Monaco. After ascending the throne, he worked assiduously and launched initiatives to revive the economy of Monaco which had been weakened since the World War II. He was also responsible for implementing reforms in Monaco's constitution and expanding its economy. Later, he became internationally known due to his fairy-tale marriage with the American movie star, Grace Kelly. But, after Kelly’s tragic death in an automobile accident, he buried himself in his work and led a solitary life, refusing to marry again. After fighting a long illness in his old age, he died at the age of 81, and was buried next to his late wife.