The 5in (13cm) oil on metal paintings in horseshoe frames make up a set of four identically presented paintings depicting Bowes’ four Derby winners – the other two are at the museum.
This pair depicting the 1835 winner Mundig and Cotherstone (the 1843 winner) are offered together with a portrait of Isaac Walker, who was head groomsman at Bowes’ Streatlam Stud from 1833-72.
They have come from a client in Matlock, Derbyshire, whose grandfather was friendly with Walker’s family.
It is not known who painted the equine portraits but they are attributed to the circle of Henry Thomas Alken (1785-1851).
They carry an estimate of £1000-1500.