Hi Liz
I cannot count myself as expert in respect of Brecknockshire, although my mother's maternal line are from neighbouring Monmouthshire and I have walked and cycled throughout the area of the old county.
You must take this response as me thinking aloud rather than offering a definitive answer. Brecknockshire, Monmouthshire and the Welsh counties running north along the border with England, and their English counterparts which would include Chester, Shropshire, Herefordshire and Gloucestershire were all in whole or in part contained within the Welsh Marches.
The purpose of the Marches was as a buffer between England and the problematic Welsh on the western side of Offa's Dyke and the Rivers Wye and Dee. In effcet the King of England created Lordships who were given near independence to develop their lands for their own ends on condition that they maintained a secure barrier against incursions from the Welsh. There were three Earldoms created to go with the areas, Chester, Shrewsbury and Hereford.
As time went on the area of the Welsh March grew, in that English dominance under their Norman aristocracy pushed further into Wales, especially in the south.
The presence of a Walter known as Sais will almost certainly not be because he used to travel frequently to England, although throughout the Marcher counties there was a great deal of movement between England and Wales and vice versa. The ruling classes from the twelfth century within the Marcher area was ethnically Norman - hence Roger! These Marcher Lordships were exept from the King of England's taxes and most other tributes and restrictions except the provision of military support when the king demanded.
Whilst Wales was not formally subsumed by the English crown until Henry VIII, every English king since William I had maintained the Marches and had pushed into Wales bit by bit. Towns such as Monmouth and Ludlow, and the now misnamed Newtown, would not exist except for these Marcher Lords. The area of Wales governed by Welsh princes after 1066 decreased steadily, and by the 1300s was restricted to the central western parts, the Lleyn peninsular and north Wales west of the River Conwy. Edward I had built his castles to intimidate and overawe the Welsh. The period you are discussing is in the reign of his grandson.
This was a period of further English (Anglo-Norman aristocracy) settlement and the founding of new great estates in Wales - and the old Welsh kingdom of Brycheniog was ripe for exploitation and it became the English dominated county of Brecknock or Brecon.
It is my belief that we are talking abut Anglo-Norman aristocrats rather than native Welsh people. The fact that they had estates on both sides of the border does not alter that fact - most did! You must remember that by this time, the old Duchy of Normandy and been lost to the English crown. This posed a real problem for most of the ruling classes, because they had had estates in both Normandy and in England. The French king had made them choose! Those remaining in England wanted the opportunity to replace their lost Norman estates which is why so many after 1200 were looking at Wales and Scotland. (Scotland was also dominated by Anglo-Normans - no matter what Mel Gibson thinks!)
I am unsure if that answers your question, but it did enable me to think aloud!
