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
Castle Cornet in 1340 and the castle was recaptured in August 1345 after a three-day attack by professional soldiers and the local militia. The French had spent their seven-year occupation improving the defences, including probably the barbican. In 1358 the French returned and the castle was taken again, but they were evicted the following year and an island traitor was executed. In 1372 Owain Lawgoch, a claimant to the Welsh throne, leading a free company on behalf of France, attacked Guernsey in an assault popularly called “La Descente des Aragousais”. Owain Lawgoch withdrew after killing 400 of the Island militia, without capturing