While the Viking Age in Britain traditionally has been quoted as AD793, then based on the Annals of Ulster then AD795 has been the year thought to be the first Viking attack in Ireland. While this may be the first surviving written record, then new analysis of skeletons found in Dublin is giving results that indicate the Vikings arrived earlier.
Carbon dating results of the skeletons are giving a date range as early as AD670. Additionally, isotopic oxygen level analysis should that several of the remains are of persons who grew up in Ireland or Scotland. This is significant because it is strong evidence of Viking settlements in the British Isles, and not just raiding going on at the time.
Combined with archaeological Anglo-Saxon artifacts recently found in both Norway and at the town of Ribe in Denmark which have been dated to pre-793, the evidence is mounting that there was interaction across the North Sea in the 7th and 8th centuries – and the real question is increasingly whether the contact was continuous from the Great Migration period and all the way up to the beginning of the Viking Age? In other words, that the contact never truly ceased.