Born in Sweden where he acquired the rudiments of painting, Wertmüller travelled to Paris in 1772 where he studied under his cousin, Alexander Roslin and Joseph-Marie Vien. In 1784, he was appointed painter to King Gustavus III of Sweden as well as being admitted into the French Academy. The following year he exhibited his widely-acclaimed portrait of Marie Antoinette and her Children, now in the Nationalmuseum, Stockholm.

Having suffered both financial and artistic difficulties, largely due to the French Revolution, in May 1794, Wertmüller arrived in America to make a fresh start. The following year, saw his portrait of George Washington, now in the Metropolitan Museum of Art, receive mixed reviews including those of his fellow artist Rembrandt Peale who described it as 'a highly finished laborious performance' with 'a German aspect'.

A year after Wertmüller's death, the contents of his studio were sold in Philadelphia on May 18, 1812, the earliest recorded catalogued public sale of works of art in America (see M.Benisovich, The Sale of the Studio of Adolph-Ulrich Wertmüller, The Art Quarterly, Spring 1953, pp. 21-39). Among the 304 lots were his portrait of Washington as well as his masterpiece Danaë, now in the Nationalmuseum, Stockholm, which was the first painting of a nude to be publicly displayed in America. Lot 19 was described as 'King and Queen of France, small ovals from person', which may be the present pictures