Born in Bath, Maine, William Prior became an itinerant portrait and landscape painter who also painted on glass. In 1841, he settled in Boston after traveling and painting widely for ten years around New England. In 1824, he had been in Portland, Maine and lived there from 1831 to 1840. He advertised in the "Maine Inquirer" in 1831 that "persons who wished a flat picture can have a likeness whithout shade or shadow at one-quarter price" (Falk).

It was this style of primitive painting for which he became best known, but he also painted on glass with more sophistication, including copies of Gilbert Stuart's "Athenaeum" portrait of George Washington and portraits of Washington and his wife Martha. In his later years, he was assisted by...