Marbury Dunne was a famous mare belonging to the Smith-Barry family. The horse is buried in Marbury Hall / Park grounds. (near the Ice-house I seem to remember). 'Marbury Dunne formed the stake in a wager, that she could run from London to Marbury between the Sunrise and Sunset of one day. This she apparently did, with time to spare.
Unfortunately in the excitement which followed, the mare found access to a water trough, quenched her thirst and died from the shock. The epitaph on her grave stone read:-
Here lies Marbury Dunne,
The finest horse that ever run,
Clothed in a linen sheet,
With silver hoofs upon her feet.