Истрад-Тиви
Rhys endeavoured to remain loyal to the English crown in the hope he may be restored to more of his former patrimony, but no such offers were forthcoming from the king – instead, Edward forced Rhys to quitclaim the castle to him in October 1283. In 1287 he rebelled and led the capture of most of Ystrad Tywi, the heartland of Deheubarth, including the castles at Dinefwr and Carreg Cennen. Though the revolt was quelled by the autumn, it broke out again in November, and was only brought to a conclusion after a ten-day siege of Rhys' final stronghold, the castle at Newcastle Emlyn, in January 1288.