English: This is one of only three known portraits of George III's youngest brother. The other two, by Knapton and Liotard, are also in the Royal Collection. Prince Frederick William was the youngest son of Frederick, Prince of Wales, and Princess Augusta of Saxe-Gotha. Horace Walpole, art historian and writer, described him as 'a pretty and a promising boy'.

The artist is thought to be Samuel Cotes (1734-1818) who was the younger son of an apothecary based in Cork Street, London. Samuel also trained as an apothecary but was taught to paint by his brother, the portrait painter Francis Cotes. He exhibited at the Society of Arts from 1760 to 1768 and at the Royal Academy from 1769 to 1789. He was married twice and his second wife, Sarah Shepherd, was an amateur painter.

The miniature is set in its original bracelet frame matching the bracelet containing another miniature of Princess Louisa (1749-68) (RCIN 420250), Frederick's older sister, also in the Royal Collection