On the matter of Matilda (Maud) de Braose, wife of Rhys Mechyll, the following note:
"I have found the record of a dispensation granted by Pope Martin IV, in a letter to Thomas, Bishop of St. Davids, dated at Orvieto on 10 December 1283. This dispensation was required because Rhys ap Maredudd and Ada de Hastings were related in the third and fourth degrees of consanguinity.
Ada de Hastings had no Welsh ancestor within 4 generations (up to her great-great grandparents), so it is evident that there is an English (or Anglo-Norman) or other non-Welsh ancestor of Rhys ap Maredudd. One possibility that I considered was Maud de Clare, widow of William de Braose (d. 1210) and wife (2ndly) of Rhys Gryg. I am not aware of any issue of this marriage of Rhys Gryg, but more importantly, the de Braose relationship this would create would be too distant (on the side of Ada de Hastings, anyway) to create a need for a dispensation.
The one other possibility was that Maredudd ap Rhys was the son of Rhys 'Mechyll' (d. 1244) by Maud de Braose, and that Maud was the daughter of Reginald de Braose (d. ca. 1228) by Grace de Briwere. This identification would yield the relationship of 3rd & 4th degrees stipulated in the dispensation...
This serves to correct the identification of Maredudd ap Rhys, father of Rhys 'Mechyll' (ex. 1292) as a son, not of Rhys Gryg ap Rhys (ap Gruffydd, aka 'the Lord Rhys'), but of Rhys 'Mechyll' ap Rhys (d. 1244) by his wife Maud de Braose. Further, this serves to confirm that this Maud de Braose was a daughter of Reginald de Braose, as previously suggested...." 1
Rhys Mechyll died in 1244 and some time after this Matilda placed the castle of Carreg Cennen in the hands of the Normans.
A Welsh chronicle, the Brut y Tywysogyon, records under the year 1248: "Rhys Fychan ap Rhys Mechyll regained the castle of Carreg Cennen, which his mother had treacherously placed in the power of the French, out of enmity for her son." 2
"Reginald de Braose also allied with Prince Rhys Mechyll of Deheubarth when his relationship with Llywelyn [ab Iorwerth] deteriorated in 1217. Rhys Mechyll married Reginald's daughter Matilda but by 1248 her hatred of her son exacerbated the family feud which finally destroyed the princes of Deheubarth. Matilda had handed Carreg Cennen over to the English and Rhys Fychan seized the castle back again in fury at his mother's treachery." 3