Sir William was a champion racehorse. He was the winner of the 1838 Grand Liverpool steeplechase, later to be known as the Grand National

Grand National

The Grand National is a world-famous National Hunt horse race which is held annually at Aintree Racecourse, near Liverpool, England. It is a handicap chase run over a distance of four miles and 856 yards , with horses jumping thirty fences over two circuits of Aintree's National Course...

. Only three runners took part, with the previous year's winner, The Duke

The Duke (racehorse)

The Duke was a racehorse that won the first Great Liverpool Steeplechase at Aintree, which would be later renamed the Grand National. His rider was Captain Martin Becher after whom the famous fence Becher's Brook was named...

, sent off as 1/2 favourite. He finished last of the three in the race. The winner was ridden by Irishman, Alan McDonough.