Lleision (dynasty)
The dynasty of the Lleision (Welsh pronunciation: ['ɬei̯sjɔn], 'descendants of Lles Llawddeog'), sometimes known as the House of Powys or House of Mathrafal, was an important Welsh family in the high Middle Ages in Wales. It came to prominence with the brothers Bleddyn and Rhiwallon ap Cynfyn, uterine brothers of the only man to rule over all Wales, Gruffudd ap Llywelyn.