Henry de Blois, King Stephen's brother, Bishop of Winchester, probably wished for a stronghold near at hand, during his brother's wars with the Empress Maud. He would have begun by having the nearly circular embankment thrown up with a parapet along the top, and in the ditch thus formed a stockade of sharp pointed stakes. Within the court, the well, 300 feet deep, was dug, and round it would have been the buildings needed by the Bishop, his household and guards, much crowded together. The entrance would have been a drawbridge, across the great ditch, which on this side was not less than 60 feet wide and perhaps 25 deep, and through a great gateway between two high square towers which must have stood where now there is a slope leading down from the inner court, into the southern one. This slope is probably formed by the ruins of the gateway and tower being pitched into the ditch. The Castle was then very small, and did not command the country except towards the south. The next work therefore would be to throw out an embankment to the south, with a ditch outside. The great gap whence Hursley House is seen, did not then exist, but there was an unbroken semicircle of rampart and ditch, which would protect a large number of men. In case of an enemy forcing this place, the defenders could retreat into the Castle by the drawbridge. The entrance was on the eastern side, and in order to protect this and the back (or northern side) of the Castle, an embankment was thrown up outside the first moat, and with an outer moat of its own. Then, as, in case of this being carried by the enemy the defenders would be cut off from the main southern gateway, a square tower was built on this outer embankment exactly opposite to the ruin which yet remains, and only divided from it by the great ditch. On either side of the tower, cutting the embankment across therefore at right angles, was a little ditch spanned by a drawbridge, which, if the defenders found it necessary to retire to the tower, could at any time be raised. The foundations of the tower and the position of the ditch can still be distinctly traced. Supposing farther that it became impossible to hold the tower, the besieged could retreat into the main body of the Castle by another drawbridge across the great ditch. This would lead them through the arch which can still be seen in the ruin, though it is partially blocked up. The room on the east side of this passage was probably a guard room.