The 2ft 4in x 3ft (71 x 91cm) oil on canvases have descended through the family of George and Samuel Worrall, who are depicted in all four pictures on their grey and dark bay mounts.
Primarily a painter of horse portraits, Sartorius met many of his patrons at the Newmarket races.
His clientele included a number of aristocratic sportsmen of the age such as Lord Derby, Lord Kingston and The Prince of Wales.
The set is priced at £78,000.