 Complete the following phrase:  Hamilton was born on 13 December 1730 or 12 January 1731 in either London or at Park Place, Berkshire, the fourth son of Lord Archibald Hamilton, governor of Jamaica, seventh son of William Douglas-Hamilton, Earl of Selkirk, by the 3rd Duchess of Hamilton, and Lady Jane Hamilton, daughter of James Hamilton, 6th Earl of Abercorn. His mother was a favourite, and possibly a mistress, of the Prince of Wales and William grew up with his son George III, who would call him his foster brother. At age nine, he went to Westminster School, where he made lifelong friends of Frederick Hervey and David Murray. Hamilton used to say that he was born with an ancient name and a thousand pounds; as a younger son he would have to make his own way in life. So, six weeks after his sixteenth birthday, he was commissioned into the 3rd Foot Guards as an ensign. He spent some time with the regiment in the Netherlands, and advanced to lieutet in 1753. In September 1757, he was present as aide-de-camp to General Henry Seymour Conway at the abortive 