 Historians have speculated that ab Einion was responsible for a manuscript titled the Red Book of Hergest which is one of the most important medieval Welsh language manuscripts.Furthermore, in 1403 ab Einion was summoned to Carmarthen by none other than Owain Glyndŵr, the last true Prince of Wales to shed light on his fate by bringing his knowledge and expertise to bare by interpreting old bardic prophecies.Before 1963 Ynysforgan essentially comprised the main Swansea to Brecon road (now Clydach Road) with houses on either side.