Hello Deacon thanks for the kind words Your wording is better regarding territory but I think that it still might specifically mention the Firth of Clyde since Northumbria ruled the area south of it for a while  how about between the Humber and the Firths of Clyde and Forth or similar But theres no great preference here either way  Oswiu chose the Roman way at Whitby in  and he died in  thereafter there was a steady erosion of Ionabased clerics in Northumbrian territory quite noticeable by Pehthelms consecration in the th century  have a look at the Skene reference I cite which suggests that both Picts and Northumbrians were working in concert in the early th century towards the Roman way in preference to the Columban way  It looks like a political process constant and steady but not a sudden forcible ouster  the end result was indeed a facilitation of Northumbrian hegemony Northumbrias fortunes were upanddown in the th century regarding its southern neighbors particularly Mercia and that is not to suggest that anyone chose Deiran preferences over Bernician ones Im aware of the substantial history of Ionabased clerics in Bernicia but times change and sometimes political entities do things for expedient reasons  The translation of Pehthelms name without stated authority is indeed sourced  the claim is made flatout so have a look at the reference cited I tried to make sure that anyone who likes to check out references can do so easily  indeed you should be able to quickly access every citation that I made in the article Regards