Charles (1735-1806) is depicted on the left wearing the uniform of the 18th Prussian Regiment (the prince of Prussia's) and the star and orange ribbon of the Order of the Black Eagle. His younger brother Frederick (1740-1805) is on the right wearing the uniform of the 1st Prussian Regiment (the Life Guards) and also with the star and ribbon of the Order of the Black Eagle. Their sister Anna Amalia (1739-1807) is in the middle.

The siblings were the children of Charles I, duke of Brunswick. Charles William married George III's older sister, Augusta, in 1764. He was made a knight of the Order of the Garter in 1765 and succeeded his father in 1780. He had a career in the military and died of wounds he received at the battle of Jena, aged 71. Frederick Augustus died unmarried. Anna Amalia married Ernest Augustus, duke of Saxe-Weimar, in 1756. Ernest died in 1758, leaving her as regent for their young son. She was a patron of art and literature, and created round her an artistic centre of intellectuals, artists, writers and musicians including Johann Wolfgang von Goethe. She was a talented musician herself and composed the music for Goethe's Singspiel Erwin und Elmire (Musical drama of Erwin and Elmire) and for Das Jahrmarktsfest zu Plundersweilern. Anna Amalia also established the Duchess Anna Amalia Library in Weimar where Goethe worked from 1797 to 1832.

In 1767, George III bought 'twenty or more Miniature or colour'd drawings copied from the German of the House of Brunswick' and this miniature was among them. They were all probably based on portraits by Johann Georg Ziesenis, the court painter who worked in Hanover, but the identity of the painter of this miniature is unknown.