George Thomas Clark, Mediæval Military Architecture in England…
“ William de Mohun was no mere adventurer. He was a great baron of the Cotentin, having the castle of Moion in la Manche. He fought at Hastings with a knightly following, and received from the Conqueror from sixty to seventy manors in Somerset, Devon, Dorset, and Wilts. These manors were in his time, or in that of his successor, combined into an Honour, as was the case with those attached to the chief seats of Plympton, Totnes, and Barnstaple. Dunster became the caput honoris. ”
