Anglo-Saxon Chronicle. 913. This year, about Martinmas, King Edward (age 39) had the northern fortress built at Hertford [Map], betwixt the Memer, and the Benwic, and the Lea. After this, in the summer, betwixt gang-days and midsummer, went King Edward with some of his force into Essex, to Maldon [Map]; and encamped there the while that men built and fortified the town of Witham [Map]. And many of the people submitted to him, who were before under the power of the Danes. And some of his force, meanwhile, built the fortress at Hertford [Map] on the south side of the Lea. This year by the permission of God went Ethelfleda (age 43), lady of Mercia, with all the Mercians to Tamworth [Map]; and built the fort there in the fore-part of the summer; and before Lammas that at Stafford [Map]: in the next year that at Eddesbury [Map], in the beginning of the summer; and the same year, late in the autumn, that at Warwick [Map]. Then in the following year was built, after mid-winter, that at Chirbury and that at Warburton; and the same year before mid-winter that at Runkorn [Map].

The River Sow rises near Fair Oak, Staffordshire [Map]. From there it flows past Outlands, Staffordshire [Map], Bishops Offley, Staffordshire [Map], Copmere End, Staffordshire [Map], Eccleshall Castle, Staffordshire [Map], Chebsey, Staffordshire [Map], Little Bridgeford, Staffordshire [Map], Great Bridgeford, Staffordshire [Map], Stafford [Map] to Baswich, Stafford [Map] where it is joined by the River Penk.

After Baswich the River Penk flows past Milford, Staffordshire [Map] to Essex Bridge [Map] where it joins the River Trent.