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 there s no great preference here either way Oswiu chose the Roman way at Whitby in 664 and he died in 670 thereafter there was a steady erosion of Iona based clerics in Northumbrian territory quite noticeable by Pehthelm s consecration in the 8th century have a look at the Skene reference I cite which suggests that both Picts and Northumbrians were working in concert in the early 8th 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 Northumbria s fortunes were up and down in the 7th century regarding its southern neighbors particularly Mercia and that is not to suggest that anyone chose Deiran preferences over Bernician ones I m aware of the substantial history of Iona based clerics in Bernicia but times change and sometimes political entities do things for expedient reasons The translation of Pehthelm s name without stated authority is indeed sourced the claim is made flat out 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