The excavations of 1963-69 on the site of Sully Castle revealed six phases of occupation ranging from the Romano-British to the 17th or 18th century. Four were medieval (phases 2-5) from which were deduced two main periods of building: I, an earthwork of the 12th century to which a stone keep was added (phases 2-3), and II, a fortified manor-house of the 13th and early 14th centuries.
Fragments of painted wallplaster of unknown date were also recovered.

RCAHMW, 2004