Princess Mary of Great Britain Princess Mary of Great Britain Princess Mary of Great Britain (5 March 1723 – 14 January 1772) was the second-youngest daughter of King George II of Great Britain and his wife Caroline of Ansbach, and Landgravine of Hesse-Kassel as the wife of Landgrave Frederick II. Princess Mary was born at Leicester House, Westminster, London. Her father was the Prince of Wales, later King George II. Her mother was Caroline of Ansbach, daughter of Johann Friedrich, Margrave of Brandenburg-Ansbach. Her father succeeded, as George II, on 11 June 1727, and she became "HRH The Princess Mary". Upon her death in 1737,
Charles Alexander, Margrave of Brandenburg-Ansbach second cousin, as King George III, when Charles was 24). After the sudden death of his elder brother Charles Frederick August on 9 May 1737, "Alexander", as he later called himself, became Crown Prince of the principality. From 1748 to 1759, he studied at Utrecht. As the young "Count of Sayn" (the county of Sayn-Altenkirchen in the Westerwald having been absorbed into the Principality of Ansbach in 1741) he travelled to Turin and Savoy. On 22 November 1754, in Coburg, Charles Alexander married Princess Frederica Caroline of Saxe-Coburg-Saalfeld (1735–1791), daughter of Franz Josias, Duke of Saxe-Coburg-Saalfeld, and Anne Sophia, Princess