The Peak seems to have known of no widespread Saxon or English settlement until after the eruption of the Danes. It is also to the Danes that the town of Derby owes its present name, and the importance which gave its title to the surrounding shire. When the marauding Scandinavian bands overran the kingdoms of Northumbria and Mercia, the value of the Derbyshire lead soon attracted their attention. Hence they established themselves strongly and built a fort at Northworthy (the earlier name for Derby), whence the valley of the Derwent branched off in different directions to the lead-mining districts. It was the common practice of the Danes to change the names of the places where they settled; Northworthy was to them an unmeaning term now that settlements of importance had been pushed on much further northward. Deoraby, or the settlement near the deer, was clearly suggested by the close propinquity of the great forests. There is no part of the county where the place and field names are of greater interest than in the Ecclesbourne valley, which leads up from Duffield to Wirksworth. The intermingling of Norse names shows that at least two distinct streams of colonists pushed their way to this valuable mining centre. In the north-eastern portion of Mercia, five of these Scandinavian hosts, each under its own earl, made a definite settlement; they became known as the Five Burghs, and formed a kind of rude confederacy. In this way Derby became linked in government with Nottingham, Stamford, Lincoln and Leicester. This combination, however, had not long been made before Ethelfleda, the Lady of the Mercians, the sister of Alfred the Great, began to win back her dominions from these pagan Norsemen, building border forts at Tamworth and Stafford. Derby was stormed by Ethelfleda in 918, after fierce fighting, and this victory secured for her for a time the shire as well as the town itself. Six years later Edward the Elder, Ethelfleda’s brother, advanced against the Danes through Nottingham, penetrating into Peakland as far as Bakewell, where he built a fort. In 941–2 King Edmund finally freed the Five Burghs and all Mercia from Danish rule. The establishment of a mint at Derby during the reign of Athelstan (924–940) is a clear evidence of the advance of civilisation. Coins minted at Derby are also extant of the reigns of Edgar, Edward II., Ethelred II., Canute, Harold I., Edward the Confessor, and Harold II.