Mohun no doubt found the tor strongly fortified, after the English manner, for not only was it a frontier fortress against the western Celts, but it must have been exposed to the piratical invasion of the Northmen, who gave name to the opposite islands of the Holms, and the not very distant port of Swansea. The place was, in fact, a natural burh on a large scale, such as Æthelflæd and Eadward the Elder were wont to throw up artificially on a smaller scale in the early part of the tenth century. There was the conical hill with its flat top for the _aula_ or _domus defensabilis_, and the courtyard below for the huts and sheds of the dependents and cattle. 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_. The Honour of Dunster was one of about eighty-six in England, though in what they differed from baronies is not precisely understood. The nucleus of either was almost always an estate held before the Conquest, added to largely by the Norman who conquered it. In all cases it extended into more than one county, and was held of the king _in capite_ by homage, fealty, and military service. By the laws of Henry I., every lord could summon his liegemen before the court, “et si residens est ad remotius manerium ejusdem honoris unde tenet, ibit ad placitum, si dominus suus summoneat eum.” The Honour is not a jurisdiction mentioned in Domesday, unless it be in a passage relating to Cornwall where it is recorded, “Hæ terræ pertinent ad honores chei;” chei being a place. The term is said to have been first used by the Conqueror in his charter to the Abbot of Ramsey. Most of the Honours seem to have fallen into disuse by the alienation of the manors composing them, as was the case with Dunster, although the records show that for many centuries the rights were maintained by the lord of the castle in full rigour.