[3] In the 12th century it was surrounded by a low artificial lake, fed by the brook to the west, and could only be accessed by causeways.

In later years the castle became owned directly by the Bishop of Durham, a powerful regional landowner.

A 10cm diameter core sample was taken, running from the top of the mound down to below the original ground level, with Radiocarbon dating of the buried material.

The great majority of the mounds investigated confirmed a Norman construction, with no sign of a previous earthwork.

It also identified that the raised causeway on the north side was a secondary feature, which had not been part of the original construction.