Definition: Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.
Input: Passage: In 1857 John Sheepshanks donated 233 paintings, mainly by contemporary British artists, and a similar number of drawings to the museum with the intention of forming a 'A National Gallery of British Art', a role since taken on by Tate Britain; artists represented are William Blake, James Barry, Henry Fuseli, Sir Edwin Henry Landseer, Sir David Wilkie, William Mulready, William Powell Frith, Millais and Hippolyte Delaroche. Although some of Constable's works came to the museum with the Sheepshanks bequest, the majority of the artist's works were donated by his daughter Isabel in 1888, including the large number of sketches in oil, the most significant being the 1821 full size oil sketch for The Hay Wain. Other artists with works in the collection include: Bernardino Fungai, Marcus Gheeraerts the Younger, Domenico di Pace Beccafumi, Fioravante Ferramola, Jan Brueghel the Elder, Anthony van Dyck, Ludovico Carracci, Antonio Verrio, Giovanni Battista Tiepolo, Domenico Tiepolo, Canaletto, Francis Hayman, Pompeo Batoni, Benjamin West, Paul Sandby, Richard Wilson, William Etty, Henry Fuseli, Sir Thomas Lawrence, James Barry, Francis Danby, Richard Parkes Bonington and Alphonse Legros. Question: What was the goal of John Sheepshanks considerable bequest to the museum?
Output:
forming a 'A National Gallery of British Art'