Settlements in and around the Black Mountains include Hay-on-Wye, Llangors, Talgarth, Crickhowell, Cwmdu, each in Powys, Abergavenny in Monmouthshire and Longtown in Herefordshire.
The Life of St. Cadoc by Lifris (c. 1100) portrays Brychan fighting Arthur, Cai and Bedivere because of King Gwynllyw of Gwynllwg's abduction of his daughter St. Gwladys from his court in Talgarth.