Urbs Iudeu

This war was fought in the area north of the River Trent, in particular in and around the Peak District (Wirksworth) also around Heathfield (Doncaster), Elmet (Aberford) and Lindsey (Lincoln), as these were provinces of Northumbria at the time.

[citation needed] In or about 616 AD, the Northumbrians, apparently attempting to expand their kingdom under King Æthelfrith, fought the native Britons and their allies at the Battle of Chester.

[4] Earlier, in a more incoherent way, some of the battles had been noted from the Northumbrian viewpoint by the Venerable Bede in his Historia ecclesiastica gentis Anglorum (Ecclesiastical History of the English People).

[5] The battles of the Northumbrian–Mercian war resulted from Northumbrian attempts to expand their kingdom, which originally comprised the provinces of Deira and Bernicia, including all the region north of the River Trent and in close proximity to it.

Its eventual outcome and legacy, however, was the development and expansion of the Mercian kingdom beyond its original focal point in the Trent Valley around Tamworth and Repton.