William, Duke of Clarence is wearing the star of the Order of the Garter. His head is based on Richard Cosway's full-length drawing of him wearing Garter robes and leaning on an anchor, which was engraved by Louis Sailliar in 1790. William IV was the third son of George III and the brother of George IV. At the age of 13, he became a midshipman and began a career in the Royal Navy, earning him the nickname 'The Sailor King'. William IV, called a monarch 'of the most strict integrity' by a contemporary, was succeeded by his niece, Queen Victoria.

Richard Cosway (1742-1821) was born in Devon, the son of the headmaster of Blundell's school, Tiverton. The family were prosperous, and owned a woollen business and property. At the age of 12, Richard was sent to London to study drawing under Thomas Hudson at Shipley's drawing school. He entered the Royal Academy Schools in 1769 and exhibited at the Royal Academy between1770 and 1806. He married Maria Hadfield in 1781, an accomplished artist herself. The couple had one daughter, who died at the age of seven. Richard Cosway's portrait of Maria Fitzherbert attracted the attention of the Prince of Wales who appointed him as his official miniature painter in 1786 and general advisor for the decoration of Carlton House, his residence in London. In 1811, however, Cosway lost the Prince's favour and his eyesight began to fail. He was eccentric and outlandish in behaviour and dress, but was an astute collector and acquired a fine collection of old master drawings. His miniatures are painted with a delicacy and fine modelling, and he developed the technique of using transparent pigments which allows the natural luminosity of the ivory to shine through.

Signed and dated on the original backing card in ink: Rdus Cosway. / R.A. / Primarius Pictor / Serenissimi Walliae / Principis / Pinxit / 1791.