Ystrad Tywi
Following his father's death, Pryderi became ruler of the seven cantrefs of Dyfed and set about expanding his territories by conquering Ystrad Tywi and Ceredigion. He was occupied with this conquest until he chose to take a wife, eventually marrying Cigfa, the daughter of Gwyn Gohoyw. He also succeeded in amalgamating the seven cantrefs of Morgannwg into his kingdom, although the conquest itself is not referenced in any texts.