Dictionary of National Biography, 1885-1900/Brochmael, Ysgythrawg
BROCHMAEL, YSGYTHRAWG (fl. 584), king of Powis, is mentioned in Llywarch Hen's elegy (trip. 37), a poem which Dr. Guest (Origines Celticæ, ii. 289) has referred to the overthrow of Uriconium and the desolation of the Severn Valley by Ceawlin, king of the West Saxons in 584. The country of Kyndylan, the chief whose death Llywarch Hen bewails, is there called the land of Brochmael, and it is probable, therefore, that Brochmael was lord of that part of Britain, and that it was under his command that the Welsh (Britons) checked Ceawlin's career of conquest at Fethan-leag or Faddiley. When in 613 (Annales Cambricæ; A.-S. Chron. 607) Æthelfrith of Northumbria overthrew the Welsh at the battle of Chester, Bæda says that the monks of Bangor who had come to pray for the success of their countrymen were under the care of Brochmael, who stayed with them while the battle was fought, and who left them and fled when the victorious Æthelfrith attacked them. In this battle Selim, the son of Cynan, was slain, and as Cynan is said to have been the son of Brochmael, it is evident that he must have been an old man at the time, and 'therefore may very well have been king of Powis when Ceawlin [q. v.] attacked Uriconium' (Guest).
[Guest's Origines Celticæ, ii. 299, 308, 326; Annales Cambriæ an. 613, Rolls Ser.; Bæda, Hist. Eccl. ii. 2 (Eng. Hist. Soc.); Anglo-Saxon Chron. an. 584, 607, Rolls Ser.]