The conflict between the Welsh princes and the English kings continued in the reign of Edward I. In 1282 Llywelyn fought a final campaign against Edward, ending in the prince's death near Builth that December. His brother, Dafydd ap Gruffydd, assumed power but during 1283 was forced south into Snowdonia. Meanwhile, forces under the command of Roger Lestrange and William de Valence marched from south Wales and Shropshire, placing Castell y Bere under siege and taking it on 25 April. Edward deployed 7,000 troops to detain Dafydd who was finally captured and executed in October. A team of five masons and five carpenters, under the command of Master Bertram the Engineer, were left at Castell y Bere to conduct unspecified work after the English army had left.