Thomas Frederick Tout , Dictionary of National Biography… (1893)
“ Next year Llewelyn was occupied in a quarrel with his eldest son Gruffydd, born of a Welsh mother, who resented the favour shown to his legitimate half-brother Davydd, the grandson of King John. The men of Meirionydd, over which Gruffydd bore sway, grievously insulted Llywelyn, who now marched against them with an army. The intervention of 'the wise on both sides' prevented bloodshed. Gruffydd sulkily submitted to Llywelyn, who took away from him his dominions of Meirionydd and Ardudwy. ”
