Pontefract is called Kirkby in some of the earlier charters, and this was evidently the English (or rather the Danish) name of the place. It lay within the manor of Tateshall, which is supposed to be the same as Tanshelf, a name still preserved in the neighbourhood of, but not exactly at, Pontefract.[583] Tanshelf claims to be the Taddenescylf mentioned in the _Anglo-Saxon Chronicle_, where King Edgar received the submission of the Yorkshire Danes in 947. There is no proof that the hill at Kirkby was fortified before the Conquest. It was a steep headland rising out of the plain of the Aire, and needing only to be scarped by art and to have a ditch cut across its neck to be almost impregnable. It lay scarcely a mile east of the Roman road from Doncaster to Castleford and the north. [Illustration: FIG. 26. Pontefract, Yorks. Preston Capes, Northants. Quatford, Salop.] It is no part of our task to trace the fortunes of this famous castle, which was considered in the Middle Ages to be the key of Yorkshire.[584] In spite of the labels affixed to the walls we venture to assert with confidence that none of the masonry now visible belongs to the days of Ilbert. The structural history of the castle was probably this: Ilbert de Lacy, one of the greatest of the Norman tenants-in-chief in Yorkshire,[585] built in this naturally defensive situation a castle of earth and wood, like other Norman castles. Whether he found the place already defended by earthen banks we do not attempt to decide, but analogy makes it fairly certain that the motte was his work, and was crowned by a wooden tower. This motte, which was at least partially scarped out of the soft sandstone rock, is now disguised by the remarkable keep which has been built up around it, consisting at present of two enormous round towers and the ruins of a third. As a fourth side is vacant, it may reasonably be conjectured that there was a fourth roundel.[586] If the plan was a quatrefoil it resembled that of the keep of York, which is now ascertained to belong to the reign of Henry III.; and the very little detail that is left supports the view that Pontefract keep was copied from the royal experiment at York, though it differed from it in that it actually revetted the motte itself. There is no ditch now round the motte, but we venture to think that its inner ditch is indicated by the position of the postern in Piper's Tower, which seems to mark its outlet. It appears to have been partly filled up during the great siege of Pontefract in 1648.[587] The platform which is attached to the motte on the side facing the bailey is probably an addition of the same date, intended for artillery; its retaining wall shows signs of hasty construction. A well chamber and a passage leading both to it and to a postern opening towards the outer ditch appear to have been made in the rocky base of the motte in the 13th century.