Beaumaris was besieged and captured by forces in Owain Glyndŵr's revolt in 1403, then retaken by royal troops in 1405. Maintenance later collapsed: rain entered the rooms, a 1539 report listed only a handful of small guns and forty bows, and by 1609 the castle was described as utterly decayed. The English Civil War restored its military value when Thomas Bulkeley spent heavily on the defenses and held it for the king until surrendering to Parliament in 1646. Royalists briefly occupied the castle again during the 1648 Anglesey revolt, but Parliament retook it and kept a costly garrison because invasion from Scotland remained a concern. That decision spared Beaumaris from deliberate demolition, although the restored Bulkeley family later stripped lead and roofing from the ruins after Charles II returned.
Chapter · 26:31-28:52
From Glyndŵr's revolt to the Civil War
Beaumaris's capture during Owain Glyndŵr's revolt, Tudor decay, and renewed Civil War garrisons show how an unfinished medieval fortress remained strategically useful for centuries.