Rhain ap Cadwgan

Rhain ap Cadwgan (English: Rhain, son of Cadwgan; died c. 740) was an 8th-century king of Dyfed and Brycheiniog in Wales of the Early Middle Ages.

Cloten married the princess of Brycheiniog and briefly united the two kingdoms. During Rhain's rule, however, King Seisyll of Ceredigion invaded Dyfed and annexed its Cantref Ystrad Tywi (c. 710). Ceredigion and Ystrad Towi were then merged to form Seisyllwg. Sometime after this, the reduced Dyfed and Brycheiniog were briefly called Rhainwg.