DBWI: What if the Northumbrians lost the Battle of Dun Nechtain

[Bronze Centurion]

In the late 7nth century the Northumbrians had begun to lose control over the Pictish kingdoms of Northern Britain. In response King Ecgfrith marched an army north and crushed the Picts at the Battle of Dun Nechtain, bringing them back under Northumbrian suzerainty and permanently tying them to the politics of the Anglo-Saxon kingdoms. But what if the Picts had won and it was the Northumbrian army that had been shattered.

Would it have just been a temporary set back or would Northumbria have been permanently locked of the far North. Could it have been the beginning of a Pictish state and what effect would all of this have had on the latter Viking invasions.

 

[The Professor]

Technically Northumbria only gained the southern kingdoms of Fife and Kirken, Fortri or Verturia still survived in the North.
Maybe Verturia could have absorbed the others, and resisted Gaelicisation and absorption into Dalriada?
Fife is almost bound to become Northumbrian as it's too close to the heart of Lothian.
I still think a weaker Northumbria would survive the loss of the south as OTL though it probably wouldn't absorb Cumbria nor regain most of its southern territory.