Harlech in Edward I's castle system

Edward I's castle building after the campaigns of 1277 and 1282 produced several different defensive plans. Caernarfon and Conwy each have a single defended area divided by a cross wall, while Flint's 1277 plan is treated as a separate design. High curtain walls, flanking towers and elaborately defended entrances provide the main defences. Beaumaris and Harlech illustrate the concentric arrangement. A lower outer curtain lets defenders on the high inner wall fire over the outer defenders' heads. Towers left open at the back give an enemy little shelter after capture because their interiors remain exposed to the inner wall. Fortified towns accompanied most of these royal castles, although Harlech is identified as the exception to that arrangement.