Prince William Henry, duke of Gloucester (1743-1805), was the fifth child of Frederick, Prince of Wales and Princess Augusta of Saxe-Gotha. In 1762, he was installed as a knight of the Garter, and he wears the ribbon and star of the Order here. William secretly married Maria, Countess Dowager of Waldegrave, niece of Horace Walpole, art historian and writer, in 1766. He only revealed the marriage to the king in 1772. George III did not approve, and the duke, duchess and their children were barred from the royal presence until 1780.

The identity of the artist is unknown but it has been suggested that it may be Richard Crosse who exhibited a miniature of the duke of Gloucester at the Royal Academy in 1771 and was later paid eight and ten guineas for two other portraits of the duke, as recorded in his fee book. Richard Crosse (1742-1810) was born near Cullompton, Devonshire. He was a deaf mute and took up miniature painting as a hobby, then went to London to study at Shipley's Drawing School. He was appointed painter in enamel to George III in 1788. He painted many leading figures of the day and was a prolific worker – in 1777 he produced about 100 miniatures. also painted a miniature of the duke's brother, Henry Frederick, Duke of Cumberland and exhibited them both at the Royal Academy.

A paper pasted to the ivory back is inscribed in pencil: D. of Gloucester / 3/ H41 / 148.