There were Roman forts at Concangis (Chester-le-Street), Lavatrae (Bowes), Longovicium (Lanchester), Piercebridge (Morbium), Vindomora (Ebchester) and Vinovium (Binchester).
Around AD 547, an Angle named Ida founded the kingdom of Bernicia after spotting the defensive potential of a large rock at Bamburgh, upon which many a fortification was thenceforth built.
Eventually, factional fighting and the rejuvenated strength of neighbouring kingdoms, most notably Mercia, led to Northumbria's decline.
[7] The arrival of the Vikings hastened this decline, and the Scandinavian raiders eventually claimed the Deiran part of the kingdom in AD 867 (which became Jórvík).
Despite their success south of the river Tees, the Vikings never fully conquered the Bernician part of Northumbria, despite the many raids they had carried out on the kingdom.
[8] St Cuthbert's remains were placed in a shrine in the White Church, which was originally a wooden structure but was eventually fortified into a stone building.
Bishop Aldhun began this process by procuring land in the Tees and Wear valleys, including Norton, Stockton, Escomb and Aucklandshire in 1018.
[9] The bishops' special jurisdiction rested on claims that King Ecgfrith of Northumbria had granted a substantial territory to St Cuthbert on his election to the see of Lindisfarne in 684.
[11] In response, in January 1069, William despatched a large Norman army, under the command of Robert de Comines, to Durham City.
The army, believed to consist of 700 cavalry (about one-third of the number of Norman knights who had participated in the Battle of Hastings),[11] entered the city, whereupon they were attacked, and defeated, by a Northumbrian assault force.
The Northumbrians wiped out the entire Norman army, including Comines,[11] all except for one survivor, who was allowed to take the news of this defeat back.
[11] William The Conqueror subsequently (and successfully) attempted to halt the northern rebellions by unleashing the notorious Harrying of the North (1069–1070).
[15] Matters regarding the bishopric of Durham came to a head in 1293 when the bishop and his steward failed to attend proceedings of quo warranto held by the justices of Northumberland.
[16] The arguments appear to have prevailed, as by the fourteenth century Durham was accepted as a liberty which received royal mandates direct.
The bishop's council, consisting of the clergy, the sheriff and the barons, regulated judicial affairs, and later produced the Chancery and the courts of Admiralty and Marshalsea.
As long as he remained loyal to the king of England, he could govern as a virtually autonomous ruler, reaping the revenue from his territory, but also remaining mindful of his role of protecting England’s northern frontier.A report states that the Bishops also had the authority to appoint judges and barons and to offer pardons.
On the outbreak of the Great Rebellion in 1642 Durham inclined to support the cause of Parliament, and in 1640 the high sheriff of the palatinate guaranteed to supply the Scottish army with provisions during their stay in the county.
In 1642 the Earl of Newcastle formed the western counties into an association for the King's service, but in 1644 the palatinate was again overrun by a Scottish army, and after the Battle of Marston Moor (2 July 1644) fell entirely into the hands of Parliament.
[17] In 1614, a bill was introduced in Parliament for securing representation to the county and city of Durham and the borough of Barnard Castle.
The bishop strongly opposed the proposal as an infringement of his palatinate rights, and the county was first summoned to return members to Parliament in 1654.
In the wake of the Reform Act 1832 the county returned two members for two divisions, and the boroughs of Gateshead, South Shields and Sunderland acquired representation.
[33][39] The reconstituted County Durham lost territory[40] to the north-east (around Gateshead, South Shields and Sunderland) to Tyne and Wear[41][42] and to the south-east (around Hartlepool) to Cleveland.
[43] The area of the Lord Lieutenancy of Durham was also adjusted by the Act to coincide with the non-metropolitan county[44] (which occupied 3,019 km2 (1,166 sq mi) in 1981).
[65] The Durham Coalfield covered a large area of the county, from Bishop Auckland, to Consett, to the River Tyne and below the North Sea, thereby providing a significant expanse of territory from which this rich mineral resource could be extracted.
King Stephen possessed a mine in Durham, which he granted to Bishop Pudsey, and in the same century colliers are mentioned at Coundon, Bishopwearmouth and Sedgefield.
[citation needed] Among other early industries, lead-mining was carried on in the western part of the county, and mustard was extensively cultivated.
[citation needed] The county's modern-era economic history was facilitated significantly by the growth of the mining industry during the nineteenth century.
According to the Encyclopædia Britannica Eleventh Edition (1911): "To the Anglo-Saxon period are to be referred portions of the churches of Monk Wearmouth (Sunderland), Jarrow, Escomb near Bishop Auckland, and numerous sculptured crosses, two of which are in situ at Aycliffe.
The Decorated and Perpendicular periods are very scantily represented, on account, as is supposed, of the incessant wars between England and Scotland in the 14th and 15th centuries.
The principal monastic remains, besides those surrounding Durham cathedral, are those of its subordinate house or "cell," Finchale Priory, beautifully situated by the Wear.