Vikings
In England the Viking Age began dramatically on 8 June 793 when Norsemen destroyed the abbey on the island of Lindisfarne. The devastation of Northumbria's Holy Island shocked and alerted the royal courts of Europe to the Viking presence. "Never before has such an atrocity been seen," declared the Northumbrian scholar Alcuin of York. Medieval Christians in Europe were totally unprepared for the Viking incursions and could find no explanation for their arrival and the accompanying suffering they experienced at their hands save the "Wrath of God". More than any other single event, the attack on Lindisfarne demonised perception of the Vikings for the next twelve centuries. Not until the 1890s did scholars outside Scandinavia begin to seriously reassess the achievements of the Vikings, recognizing their artistry, technological skills, and seamanship.
Kingdom of the Isles
Prior to the Viking incursions the southern Hebrides formed part of the Gaelic kingdom of (or Dalriada). North of , the Inner and Outer Hebrides were nominally under Pictish control although the historical record is sparse. According to Ó Corráin (1998) "when and how the Vikings conquered and occupied the Isles is unknown, perhaps unknowable", although from 793 onwards repeated raids by Vikings on the British Isles are recorded. "All the islands of Britain" were devastated in 794 with Iona being sacked in 802 and 806. Various named Viking leaders, who were probably based in Scotland, appear in the Irish annals: in 837, in 845 and in 847. Another early reference to the Norse presence in the Irish records is that there was a king of "Viking Scotland" whose heir, , took an army to Ireland in 848.