<P> The Isle of Man had supported its own agrarian population, but it is widely believed that it was Brythonic - speaking before Old Irish (later to become Manx) spread there . Gaelicisation could have taken place before the Viking age or perhaps during it, when the area was settled by Norse - Gaels who practised their own culture . </P> <P> In northern Britain, in the area roughly corresponding to modern - day Scotland, lived three distinct ethnic groups in their own respective kingdoms; the Picts, Scots and Britons . The Pictish cultural group dominated the majority of Scotland, with major populations concentrated between the Firth of Forth and the River Dee, as well as in Sutherland, Caithness, and Orkney . The Scots were, according to written sources, a tribal group which had crossed to Britain from Dalriada in the north of Ireland during the late 5th century . Archaeologists have not been able to identify anything that was unique to the kingdom of the Scots, noting similarities with the Picts in most forms of material culture . The Britons were those dwelling in the Old North, in parts of what have become southern Scotland and northern England, and by the 7th or 8th centuries, had apparently come under the political control of the Anglo - Saxons . </P> <P> By the mid-9th century, Anglo - Saxon England was divided into four separate and independent kingdoms; East Anglia, Wessex, Northumbria, and Mercia, the latter of which was the strongest military power . Between half a million and a million people lived in England at this time, with society being rigidly hierarchical . This class system had a king and his ealdormen at the top, under whom were the thegns, or landholders, and then the various forms of agricultural workers below them . Beneath all of these was a class of slaves, who may have made up as much as a quarter of the population . The majority of the populace lived in the countryside, although a few large towns had developed, namely London and York, which were centres of royal and ecclesiastical administration . There was also a number of trading ports, such as Hamwic and Ipswich, where foreign trade took place . </P> <P> Society in 8th century Scandinavia was, unlike parts of the British Isles, still pre-literate, existing in the final stages of European prehistory, known to archaeologists as the Iron Age . In Scandinavia, the 8th century proved to be "a period of rapid technological, economic and social development" which would lead the region out of the Iron Age and into what has come to be known as the Viking Age . </P>

When did the vikings first set sail and reach the shores of britain