The source is a half-length oil portrait by Ferdinand Krumholz (1810 – 78) signed and dated 1845 in the Royal Collection (RCIN 403668) and copied by Simpson, according to the Enamels inventory, in 1850. Since their first visit to England in 1836 with their father, Duke Ferdinand of Saxe-Coburg, Prince Ferdinand and his brother Prince Augustus had been held in the highest affection by Queen Victoria. She shared with Prince Ferdinand a love of drawing and sketching, and several of the watercolour sketches he gave her remain in the Royal Col-lection.

John Simpson (1811-after 1871) was trained as a porcelain painter at the Derby porcelain factory before moving to London in 1845. He soon established a practice as a miniature painter specialising in works on enamel, and fulfilled the first of many commissions for Queen Victoria in that year. He is last recorded describing himself at the end of his career as a 'photographic artist' (1871 census return); the date of his death is not known.

Signed and inscribed on the counter-enamel in red paint: Prince Ferdinand of Saxe Coburg / and Gotha King of Portugal / Born Octr 29 1816 / Simpson after Krumholtz