Princess Caroline Louise Marguerite of Monaco (born 23 January 1957) is Princess of Hanover by marriage to Prince Ernst August. As the eldest child of Rainier III, Prince of Monaco, and Grace Kelly, she is the elder sister of Albert II, Prince of Monaco, and Princess Stéphanie. She was Hereditary Princess of Monaco and heir presumptive to the Monegasque throne from her birth in 1957 until her brother Albert was born the following year, and again from Albert's accession in 2005 until the birth o ...