(Gwynedd), near Bangor, was begun in 1283 and was substantially complete by 1287. The castle is similar to Caernarfon and like it was planned from the first with an adjoining walled town. The work involved the uprooting of the abbey of Aberconwy, the principal Cistercian abbey in Wales
, to a new site at Maenan, 8 miles further up the river. The unfinished abbey church was taken over and completed as the parish church of the new town, which it still is. It was here that Richard II received Henry Percy, earl of Northumberland
, as Henry Bolingbroke's ambassador, and accepted assurances of safe conduct which proved to be false. During the Civil War
the castle was repaired, supplied, and garrisoned, at his own expense, for the king by John Williams
, archbishop of York, a Conwy-born man. Parliamentary forces besieged the castle, which was eventually surrendered by Williams to prevent his native town from being destroyed. For the next five years it was kept on a war footing by Parliament before being slighted in 1655.