was only referred to as Duke of Rothesay. Some others include John, brother of King Richard I and later King John, who is sometimes called Prince John. After the accession of King George I of Great Britain (the first monarch from the House of Hanover), it became customary for the sons of the sovereign and grandsons of the sovereign in the male line to be titled 'Prince' and styled His Royal Highness (abbreviated HRH). Great-grandsons of the sovereign were princes styled His Highness (abbreviated HH). The first male-line great-grandchild of a British monarch was not born until 1776. In keeping with tradition, he was given the style of His Highness Prince William of Gloucester (later Prince William Frederick, Duke of Gloucester and Edinburgh). On 22 July 1816 when he married his cousin and daughter of King George III, he was granted the style His Royal Highness. His only surviving elder sister, Princess Sophia of Gloucester, was also elevated to Her Royal Highness style the following day. Prince William died in 1834 before the accession of Queen Victoria. The first of the second set of male-line great-grandchildren of a British monarch was born on 21 September 1845 as Prince Ernest Augustus. He was granted the style of His Royal Highness because he was a male-line grandson of the King of Hanover and heir to the heir of that kingdom. Just three weeks after the birth of her fourth grandchild but first male-line grandson, Victoria issued letters patent in 1864 which formally confirmed the practice of calling children and male-line grandchildren His Royal Highness with their titular dignity of Prince or Princess prefixed to their respective Christian names. The letters patent did not address the styling of great-grandchildren or further descendants as His/Her Highness or Prince or Princess. Subsequent to 1864 some amendments regarding princes were made, with the issuance of specific letters patent changing the title and style of the following groups: In 1898, the children of Prince George, Duke of York, the eldest living son of the Prince of Wales, were customarily titled princes, with the style of Highness, as great-grandchildren of Victoria in the male line. With letters patent dated 28 May 1898, the Crown granted the children of the eldest son of any Prince of Wales the style of Royal Highness. In 1914, the children of Ernest Augustus, Duke of Brunswick, a great-great-grandchild of George III, were granted