The name "redenor" is first mentioned in the Annales Cambriae around 1196 AD when the "Lord Rhys" burned things down. In the Welsh it was known a Maes-hyfed and Maes-hyfaidd which implies the place where a summer-like fair was held. I guess that is why one from another area wanted to burn things to the ground.
William Jones appears in the legal records between 1547 - 1553. [Bundle 14/No. 96] He seems to continue his legal activity through 1579 appearing often in debt during this time. The spelling Jevan appears as early as 1538 [Bundle 1015/No. 76] such as "Jevan ap Mezzer" of Woebley. The "seizure of goods and occupation of mortgaged lands..." was the cause of several legal actions. This again shows the transition between implementation [Act of Union 1536], and the reality of new laws upon the land.
A discussion of Radnorshire can be found in Nicholas, Vol. II, p. 912 - 927.