From his base in Pembrokeshire he was a mainstay of the English campaigns against Llywelyn ap Gruffudd and later Dafydd ap Gruffudd; in the war of 1282–3 that led to the conquest of Wales he negotiated the surrender of one of Dafydd's last remaining castles, Castell-y-Bere, with its custodian, Cynfrig ap Madog.