Истрад-Тиви
Ystrad Tywi (, "Valley of the Tywi") is a region of southwest Wales situated on the both banks of the River Tywi. Although Ystrad Tywi was never a kingdom itself, it was historically a valuable territory and was fought over by the various kings of Dyfed, Deheubarth, Seisyllwg, Gwynedd, Morgannwg and the Normans.