Indeed Yorkshire is the epicentre of The NorthYorkshire, so maybe that’s the epicentre, if not the start, of the The North
More seriously, it's remarkable how a map of 8th century Southern Britain correlates well with people and culture I observe today, although the power of London does make itself felt in cities as far North as York and Leeds, something which has occurred since the 1980s. Something Mark Tewdwr-Jones of Newcastle University picked up on fairly recently, it's odd to see as someone who grew up when things were very different.
Danelaw stretched roughly from the Thames estuary to the Dee estuary and left a deep mark on our land. The Normans (themselves of Viking heritage) then took over much the southern half of Britain and were responsible for near total decimation of 'The North'.
More broadly, pre-Roman Brigantia closely resembles what I would consider as 'The North'. It's very likely that Hadrian's Wall was built as much to prevent the formation of closer association between the Brigantes and tribes in what is now Lowland Scotland, against the occupying Roman forces, as a border wall.