Criccieth Castle a distant relation of Llywelyn ap Gruffudd, began an uprising against English rule that spread quickly through Wales. Several English-held towns were razed and Criccieth (along with Harlech Castle and Aberystwyth Castle) were besieged that winter. Its residents survived until spring when the castle was resupplied. In the 14th century the castle had a notable Welsh constable called Hywel ap Gruffydd, known as Howell the Axe, who fought for Edward III at the Battle of Poitiers in 1356. The castle was used as a prison until 1404 when Welsh forces captured the castle during the rebellion of Owain Glyndŵr. The
Usk Castle early 15th century. It was here, against this background, in 1352, that Adam of Usk was born. The rebellion of Owain Glyndŵr, between 1400 and 1405, brought significant conflict to the area once again, and the Welsh forces of Owain Gyndwr attacked Usk town in 1402. The Battle of Pwll Melyn was fought nearby, and the region only stabilised under the efforts of local Welsh warrior and ally of King Henry IV of England and Monmouth-born Henry V, Davy Gam. After the rebellion the castle passed to the Duchy of Lancaster, and, with stability restored, no further redevelopment or refortification