In 1237, under the Treaty of York, Alexander II of Scotland abandoned his forefathers’ claims to Northumbria and Cumbria, and set the boundary between the two kingdoms as running between the Solway Firth (in the west), and the mouth of the River Tweed (in the east), as it still does today.
I 1237 under freden i York, opgav Alexander 2. af Skotland sine forfædres ret til Northumbria og Cumbria, og satte grænsen mellem de to kongeriget mellem Solway Firth (i vest), og flodmundingen af floden Tweed (i øst), som den også er defineret i dag.