In the development and Christianising of the widespread Mercian kingdom, South Derbyshire played a very considerable part. Repton, on the banks of the Trent, is mentioned in the Anglo-Saxon Chronicle in the year 755 in the account of the slaying of Ethelbald, the Mercian king. The same Chronicle also records the visit of the devastating Danes to Repton in 874, when they made that town their winter quarters. The founding of an abbey at Repton early in the seventh century, and the same place becoming the first seat of the Mercian bishopric from 654 to 667, is dealt with in another part of this volume and need not be named further in this sketch.

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.

The division of Derbyshire among the conquering Normans, together with the social conditions of the times, so far as they can be gathered from the entries in the Domesday Survey, have been admirably treated of at length in the recently issued opening volume of the Victoria History, to which reference has already been made. The number of manors held by the Conqueror in this county was very considerable. He derived his Derbyshire possessions from three sources. In the first instance he succeeded his predecessor, the Confessor, in a great group of manors that stretched without a break across the county in a north-easterly direction from Ashbourne to the Yorkshire borders near Sheffield. The second division of the Kings’ land consisted of the forfeited estates of Edwin, the late earl of the shire, and grandson of Earl Leofric of Mercia. These lay in a widespread group along the Trent south of Derby, and included Repton, so famous in earlier Mercian history. In the north of the county the King also secured a very considerable number of manors which had belonged to various holders, such as Eyam and Stony Middleton, Chatsworth and Walton, and a considerable group round Glossop.

There were two ecclesiastical tenants-in-chief in the county, namely, the Bishop of the diocese, who held Sawley with Long Eaton, and the manor of Bupton in Longford parish, and the Abbot of Burton-on-Trent, who held the great manor of Mickleover and several others which nearly adjoined the Abbey on the Derbyshire side.

By far the largest Derbyshire landholder was Henry de Ferrers, lord of Longueville in Normandy, whose son in 1136 became the first Earl of Derby. He held over ninety manors in this county, but the head of his barony, where his chief castle was, lay just outside the border of Derbyshire, at Tutbury. Just a few of the smaller landholders seem to have been Englishmen, confirmed in their rights by the Conqueror. In one case it can be definitely said that an Englishman not only held land at the time of the survey, under Henry de Ferrers, but became the ancestor of a family which continued for centuries to hold of Ferrers’ successors. This was “Elfin,” who held Brailsford, Osmaston, Lower Thurvaston, and part of Bupton. During the reigns of William the Conqueror and his two sons, Rufus and Henry, genuine historical particulars relative to the county are almost entirely absent. When persistent civil war raged for so long a time over the greater part of England during Stephen’s reign, Derbyshire was but little disturbed, for the leading men of the county adhered loyally to the King and held its several fortresses on his behalf. In the great Battle of the Standard, fought against the Scots at Northallerton in 1138, Derbyshire played the leading part in winning the victory; its chief credit being due to the valour of the Peakites under Robert Ferrers. Ralph Alselin and William Peveril, two other Derbyshire chieftains, were also among the successful leaders of the battle.

Peak Castle, built by William Peveril in the days of the Conqueror, passed to the Crown in 1115 on the forfeiture of his son’s estates. The Pipe Roll of 1157 shows an entry, repeated annually for a long term of years, of a payment of four pound, ten shillings, and two watchmen, and the porter of the Peak Castle. In that year Henry II. received the submission of Malcolm, King of Scotland, within the walls of this castle. There are records of other visits made to this castle by Henry II. in 1158 and 1164.

In this reign a variety of interesting particulars relative to the castles of Bolsover and the Peak can be gleaned from the Pipe Rolls, particularly with regard to their provisioning, garrisoning and repairing between 1172 and 1176, during the time of the rising of the Barons. Richard I., at the beginning of his reign, gave the castles of the Peak and Bolsover to his brother John, who succeeded to the throne in 1199. In 1200, King John was at Derby and Bolsover in March, and at Melbourne in November. This restless King’s visits to the county were frequent throughout his reign, and included a sojourn at Horsley Castle in 1209. During this turbulent reign Derbyshire was again fortunate in escaping any material share of civil warfare. The party of the Barons gained but little support, for the three notable fortresses of Castleton, Bolsover and Horsley were held for the King with but slight intermission.

In any historic survey of Derbyshire, however brief, it must not be forgotten that the Normans, for the convenience of civil administration, linked together this county and Nottinghamshire, giving precedence in some respects to the latter. The Assizes, for instance, up to the reign of Henry III., were held only at Nottingham, and the one county gaol for the two shires was in the same town. From the beginning of the reign of Henry III. up to the time of Elizabeth, the Assizes were held alternately at the two county towns. During the whole of this period there was but one sheriff for the two shires; it was not until 1566 that they each possessed a sheriff of their own.