Doubtless one of the chief reasons why the Romans were so determined to occupy, after a military fashion, the north of the county was because of the lead mining which they so actively pursued. The chief district of this lead mining extended between Wirksworth on the south and Castleton on the north. Between these two places groups of disused mines appear with frequency. Most of those that have been closely examined yield obvious traces of having been worked by our conquerors. Six pigs of inscribed Roman lead have been found in the county. One of them bears the name of Hadrian (A.D. 117–138). The probabilities, however, are strong that the Roman miners were at work in this county half a century earlier, for there is evidence of lead working in western Yorkshire in A.D. 81, and it is most unlikely that mining began in that part of Yorkshire before Derbyshire had been touched. It is scarcely possible to exaggerate the interest and importance pertaining to Dr. Haverfield’s article on Romano-British Derbyshire, as set forth in the first volume of the _Victoria History_ of the county. When the Romans left this county at the dawn of the fifth century, the first English or Saxon settlement speedily followed. The north of Derbyshire formed the southern extremity of that long range of broken primary hills—termed the Pennine Chain—which extended from the Cheviots down to the district long known as Peakland or the Peak. As the Romans withdrew, Peakland seems to have been overrun by hordes of the Picts; but when the pagan English settled in Northumbria a new element of strife was introduced which affected the line of Pennine Hills from end to end. This range became a boundary between two hostile races dissimilar in habits, tongue and creed. The older British race, Christianized to a considerable extent, took up their position on the western side, and also held their own in certain parts of the actual dividing ridge. It seems likely that the Peakland, for about 150 years after the first coming of the English—and possibly other parts to the east and south afterwards known under the common name of Derbyshire—was retained by the Celts, or Welsh, after the same fashion as they undoubtedly held the districts round the modern town of Leeds.