It looks to me like the grail itself was painted in by another artist- the perspective is wrong, the colors don’t quite match – almost looks like a sticker pasted on…
Abbey was born in Philadelphia in 1852. He studied art at the Pennsylvania Academy of the Fine Arts under Christian Schuessele. Abbey began as an illustrator, producing numerous illustrations and sketches for such magazines as Harper’s Weekly (1871–1874) and Scribner’s Magazine. His illustrations began appearing in Harper’s Weekly at an early age: before Abbey was twenty years old. He moved to New York City in 1871. His illustrations were strongly influenced by French and German black and white art. He also illustrated several best-selling books, including Christmas Stories by Charles Dickens (1875), Selections from the Poetry of Robert Herrick (1882), and She Stoops to Conquer by Oliver Goldsmith (1887). Abbey also illustrated a four-volume set of The Comedies of Shakespeare for Harper & Brothers in 1896.
He moved to England in 1878, at the request of his employers, to gather material concerning Robert Herrick, and he settled permanently there in 1883. In 1883, he was elected to the Royal Institute of Painters in Water-Colours.
He was made a full member of the Royal Academy in 1898. In 1902 he was chosen to paint the coronation of King Edward VII. It was the official painting of the occasion and, hence, resides at Buckingham Palace. He did receive a knighthood, although some say he refused it in 1907. Friendly with other expatriate American artists, he summered at Broadway, Worcestershire, England, where he painted and vacationed alongside John Singer Sargent at the home of Francis Davis Millet.
He completed murals for the Boston Public Library in the 1890s. The frieze for the Library was titled “The Quest and Achievement of the Holy Grail”. It took Abbey eleven years to complete this series of murals in his England studio.
In 1904 he painted a mural for the Royal Exchange, London Reconciliation of the Skinners & Merchant Taylors’ Companies by Lord Mayor Billesden, 1484.
Another Usaian (thanks Sarah Hoyt!) who overcame a lack of formal education through raw talent and determination.