Note 279 — Chapter X · THE EDWARDIAN CASTLE AND THE CONCENTRIC PLAN

All these gatehouses, like the gatehouse at Rockingham and others of the same period, have a central passage, flanked by round towers towards the field. Traitors’ gate, however, has an entrance of great breadth, wide enough to admit a boat from the river; and the interior is an oblong pool, without flanking guard-rooms. The round towers cap the outer angles, but are of relatively small importance in the plan. The interior pool is actually part of the ditch between the outer ward and the Thames, and the gateway is “a barbican ... placed astride upon the ditch” (Clark, ii. 242).