[urbanspaceman]

You can look no further than Newcastle, sometimes occupied by the Scots, sometimes the English, as an example of shifting loyalties... rather than divided loyalties - which, of course, constantly prevailed:

The North of England had long been viewed by those in the South as a den of Popery. "Half of the population is of the Popist faith and the other half are well-disposed towards it" wrote one Southerner. Actually, half of England's population were indifferent to religion back then, the remaining half were divided about 50/50: Catholic/Protestant.

In August 1688, the Mayor and Corporation of Newcastle sent congratulations to King James (VII/II) on the birth of his son: "…a blessing on the Prince of Wales". But in November of the same year, after the Glorious Revolution, that same Mayor and Corporation declared their allegiance to the Prince of Orange (William III) with the mob dragging the statue of a mounted King James from its base on the riverside and throwing it into the river.

The Romans made a right dammed mess of life around the Tyne - which was never a natural border, as observation of sheep farming practices will show.

Most of Northumberland remained essentially Scottish in the wake of the Roman occupation, but the loyalty of Northern barons, during the reign of King John, were never secure, and Westminster preferred to deal in bribery and corruption in an attempt to ensure a secure buffer zone. Hence the glorious opportunities for the clans.