Sir Robert is wearing his Treasury robes with the ribbon and star of the Order of the Garter. This miniature is based on an original portrait by the artist, painted from life after the battle of Dettingen in 1743, which was owned by the sitter's son, Horace Walpole (Manchester Art Museum). Walpole was nearly 70 and had retired from office at the point when he was portrayed. The enamel is one of the last portraits painted by Christian Frederick Zincke before his retirement.

Walpole was Prime Minister and Chancellor of the Exchequer from 1715-17 and again from 1721-42. He rebuilt Houghton, the family home in Norfolk, and formed an extensive collection of works of art which was sold by his eldest son to Catherine the Great. Much of it can still be seen in the Hermitage Museum, St Petersburg.

The artist, Christian Frederick Zincke (1683/4-1767), was born in Dresden, the son of a goldsmith. He settled in England in 1706 and studied enamel painting under Charles Boit. Boit was Enamel Painter to the Court until Queen Anne died in 1714 when he moved to France and Zincke took over much of his work. Zincke developed a thriving business, at first copying portraits by Sir Peter Lely and Sir Godfrey Kneller, then painting from life. He worked extensively for the royal family and, perhaps because he spoke German, was one of the few artists George II could tolerate. By 1730 he was well established at court and in February 1732, was appointed Cabinet Painter to Frederick, Prince of Wales, George II's eldest son. His eyesight began to fail, however, and he lamented: 'I find my Eyes scarce Capable of seeing them fine strokes'. By 1752 he had retired and only painted for his own pleasure. George II commented that Zincke's portraits were 'beautiful and like'.