Sir Nathaniel Curzon, 5th Bt. (1726-1804), later 1st Baron Scarsdale was a major patron of Hone, whose distinguished double portrait of him and his wife, now at Kedleston, was foreshadowed in a pioneering project for a saloon in the house by James 'Athenian' Stuart. Curzon's main achievement was the building and decoration of Kedleston, Robert Adam's interiors of which are among the most complete expressions of mid-18th Century taste to survive. Animal subjects are very much the exception in Hone's oeuvre: an autograph version of the present picture remains in the Scarsdale collection at Kedleston.
Jason, a grey colt foaled in 1749 by Standard out of a mare by the Beaufort Arabian, was bred by Sir Nathaniel Curzon and raced by him until sold to Sir James Lowther in 1756. He was firstly named Bredwardine Castle and won his first two races as such before his name was changed. He was one of the most successful horses of the period and won the Jockey Club Plate in 1757. Between 1753 and 1760, he ran in eighteen races and won fourteen (plus four walkovers) including victories over Whistlejacket, Brilliant and Sweepstakes.