William Hunt, Dictionary of National Biography… (1885)
“ AYMER de Valence (d. 1324) , Earl of Pembroke and lord of Montignac, was the third son of William of Valence, half-brother of Henry III and of Joan, daughter of Warine of Munchensi. His elder brothers died during the lifetime of their father, and Aymer succeeded to the earldom in 1290. He served in Flanders in 1297, and in Scotland in 1298. ”
