Aberwyvern castle is a fictitious medieval castle built in 13th century Wales. David Macaulay to explain the construction and features of such a fortification.
The castle is fictional but the historical context is real. Macaulay places its construction in North West Wales between 1283 and 1288, when Edward I of England was in fact building a string of castles to help his conquest of that land. Much of the layout and architecture of Aberwyvern castle is extrapolated from these Welsh castles, which Macaulay visited as a boy, and in particular Harlech Castle, which it closely resembles in design, siting and general appearance.
The castle is constructed on a rocky mount jutting out into the River Wyvern. It is square in plan and has two concentric lines of fortification. The first line of defence is an outer curtain wall of 300 feet on the side, encircling the entire castle and forming the outer ward. The outer curtain wall of the castle also links with the defensive wall of the town. The tops of the wall are furnished battlements with merlons to protect defenders arrayed along the parapet walk. There are two gatehouses, one, defended by a drawbridge leading to the town, the other to a fortified dock (to allow the garrison to be supplied by ship in the event of a siege).
Within the outer ward, stands the inner ward, defended by a curtain wall with a large tower at each of its four corners and a massive gatehouse on the side facing the town. The walls of the inner ward are 12 feet thick and considerably taller than those of the outer ward, allowing the defenders to fire over the outer defences. The inner gatehouse protects the main entry, with a portcullis and a fortified corridor lined with arrow loops and murder holes, and closed by huge doors at both ends.
The constructions within the inner ward of the castle include apartments, barracks, a forge, a kitchen and an impressive great hall.
Macaulay also details the architecture and other aspects of the construction of the walled town (also called Aberwyvern) next to the castle and explains how it supported the castle and vice versa. He explains its evolution over the centuries showing how, eventually it survives while the castle becomes a ruin.