Tudor Trevor (JC-1) is identified as "Founder of The Tribe of The Marches". He is perhaps the most well documented of the folks residing among the Welsh family groups. There are at least 15 family surnames that claim their descent from this individual. My own "Jones of Llwynon" being one of these family groups. The figure below shows a listing of these family surnames, with several branching to multiple branches.
Tudor Trevor (JC-1) is described as being "Lord of Hereford, Whittington, and Both Maelors". By this generation, it would appear that Oswestry has been lost [perhaps in exchange for Hereford], and a section of the "south" had been added. Of course, Hereford was a very slippery slice of land to hang on to. It must have been from this point that Whittington became the location of the families settlement.
[Please note that you can click on the picture to enlarge the view.]