The Domesday Book mentions ponies in Exmoor in 1086. Mentions of the ponies are rare between then and 1818, when the Royal Exmoor Forest was sold to a private buyer. Sir Thomas Acland, the Exmoor Royal Forest's last warden, took 30 ponies from the area to Winsford Hill, where he owned land. This herd became known as the Anchor herd, and a small number of descendants of this original herd still remain at Winsford Hill. At the same time as Acland's removal, the rest of the ponies were sold, but some stayed with breeders in the area, and their families still preserve the descendants of those animals. From the 1820s to 1860s Exmoors were used to produce crossbreds, which although successful were not as hardy as their ancestors. In 1893, the ponies were described in Sidney's Book of the Horse as around hands high, usually bay in color, and with conformation similar to what it is today. In the late 1800s, the National Pony Society began to register Exmoors and Exmoor crossbreds. In 1921, the Exmoor Pony Society was formed, and published its first stud book in 1963.