'The Little Dun Mare' (also known as 'I'Anson's Racehorse' in some recordings, although the Watersons version of the song is closer to 'Creeping Jane' in a number of ways ) has considerably more racing detail; Little Dun 'with her two cropt ears,' owned by a 'Charles I'Anson' takes on 'Mr. Oliver's lively bay' at Newmarket and the punters continue to make and change their bets at each post; at the end of the race, when Little Dun wins, it's discovered that she carried 12 pounds more than the colt.

It's presumed that the song is referring to the renowned Yorkshire racing family of William I'Anson (although there was no Charles), known for standing stallions such as John O'Gaunt (discussed earlier here in a post about Ouija Board's ancestry) and breeding champion mares like Blink Bonny, winner of the 1857 Derby and Oaks -- more specifically, winner of the Oaks two days after winning the Derby (and who was small as a foal, but certainly was not a dun). She later went on to produce English Triple Crown winner Blair Athol.

If the song does refer to any of William I'Anson's horses specifically, it is more likely to be Haricot, born in 1847 (and an older half-sister to Blink Bonny out of the legendary broodmare Queen Mary) -- she was considered so small and unlikely a racer that I'Anson used her as a riding horse for some time before realizing her racing potential. Her descendants include Charismatic and Rock of Gibraltar (who was second in the 2002 Breeders' Cup Mile.).