He succeeded as George III on 25 October 1760, and created William Duke of Gloucester and Edinburgh and Earl of Connaught on 19 November 1764.

[2] He initially wished for active service in the military, but his health and intelligence both proved insufficient.

The Duke and Maria lived at St Leonard's Hill in Clewer, near Windsor and had three children, all of whom were styled Highness from birth and used the territorial designation of Gloucester in conjunction with their princely styles, as great-grandchildren in the male line of George II.

[4] The same year he was made Warden of Windsor Forest, gaining the post's official residence at Cranbourne Lodge.

[10] In 1780, the Duke was made a Fellow of the Royal Society and remained interested in medical and scientific matters of the day.

[13][14] In 1825, Sir William Beechey exhibited his portraits of both Martineau and the Duke at the Royal Academy.