The castle is built of Roman stones used over again, with rows of tiles introduced between the courses with much decorative effect.[372] The original doorway was on the first floor, as in most Norman keeps; but at some after time, probably in the reign of Henry I.,[373] the present doorway was inserted; and most likely the handsome stairway which now leads up from this basement entrance was added, as it shows clear marks of insertion. Henry II. was working on the walls of the castle in 1182, and it may be strongly suspected that the repairs in ashlar, and the casing of the buttresses with ashlar, were his work.[374] One item in the accounts of Henry II. is £50 "for making the bailey round the castle."[375] There were two baileys to the castle of Colchester--the inner one, which scarcely covered 2 acres, and the outer one, which contained about 11. The inner bailey was enclosed at first with an earthwork and stockade, the earthwork being thrown up over the remains of some Roman walls, whose line it does not follow. Afterwards a stone wall was built on the earthwork, the foundations of which can still be traced in the west rampart.[376] The outer bailey, which lay to the north, extended on two sides to the Roman walls of the town; on the west side it had a rampart and stockade. If the £50 spent by Henry II. represents the cost of a stone wall round the inner bailey, then the _palicium_ blown down by the wind in 1219 must have been the wooden stockade on the west side of the outer bailey.[377] The question is difficult to decide, but at any rate the entry proves that as late as Henry III.'s reign, some part of the outer defences of Colchester Castle was still of timber. The position of Colchester Castle is exceptional in one respect, that the castle is almost in the middle of the town. But this very unusual position is explained by Mr Round's statement that the land forming the castle baileys, as well as that afterwards given to the Grey Friars on the east, was crown demesne before the Conquest, and consequently had been cultivated land, so that we do not hear of any houses in Colchester being destroyed for the site of the castle.[378] But by keeping this land as the inalienable appendage of the royal castle William secured that communication between the castle and the outside country which was so essential to the invaders. The value of the city of Colchester had risen enormously at the date of the Survey.[379]