 Given what is known about the frequency of sea transport around the Hebrides and Orkney in the 7th century it is highly likely that Gaelic and Pictish sailors were aware of Scandinavia before the commencement of the Viking Age.It has also been suggested that an assault by forces from Fortriu in 681 in which Orkney was "annihilated" may have led to a weakening of the local power base and helped the Norse come to prominence.Scholarly interpretations of the period "have led to widely divergent reconstructions of Viking Age Scotland" especially in the early period and Barrett (2008) has identified four competing theories, none of which he regards as proven.