Acre was only a small manor in Saxon times; its value at the time of the Survey had risen from 5_l._ to 9_l._[348] [Illustration: FIG. 12. Carlisle. Castle Acre, Norfolk.] CHEPSTOW (Estrighoel or Strigul), Monmouthshire.--Notwithstanding the fact that there is another castle of the name of Strigul about 9 miles from Chepstow (known also as Troggy Castle), it is clear that Chepstow is the castle meant by Domesday, as the entry speaks of ships going up the river, a thing impossible at Strigul.[349] The castle occupies a narrow ridge, well defended by the river on one side, and on the other by a valley which separates it from the town. There are four wards, and the last and smallest of all seemed to the writer, when visiting the castle, to mark the site of a lowered motte. This opinion, however, is not shared by two competent observers, Mr Harold Sands and Mr Duncan Montgomerie, who had much ampler opportunities for studying the remains. This ward is now a barbican, and the masonry upon it belongs clearly to the 13th century; it occupies the highest ground in the castle, and is separated from the other wards, and from the ridge beyond it, by two ditches cut across the headland. The adjoining court must have belonged to the earliest part of the castle, as it contains a very remarkable early Norman building (splendidly restored in the 13th century) which is regarded by most authorities as the original hall of William FitzOsbern. It must, however, have combined both hall and keep, otherwise the castle was not provided with any citadel, if there was no motte.[350] What is now the second ward has a Norman postern in the south wall, and may have been the bailey to the keep. All the other masonry is of the late Early English or the Perpendicular period, and the entrance ward is probably an addition of the 13th century. The shape of all the baileys is roughly quadrangular, except that of the fourth, which would be semicircular but for the towers which make corners to it. The whole area of the castle is 1-2/3 acres. We are not told what the value of the manor was before William FitzOsbern built his castle there, but from the absence of this mention we may infer that the site was waste. It paid 40_s._ in his time from ships' dues, 16_l._ in his son Earl Roger's time, and at the date of the Survey it paid the king 12_l._[351] Chepstow was not the centre of a large soke, and it appears to have owed all its importance to the creation of William FitzOsbern's castle.