In 669 the Annals of Ulster record the following entry: Itarnan et Corindu apud Pictores defuncti sunt.
[3] Clancy also writes that Ethernan and Corindu may have been "Gaels who died in foreign lands, but neither name is well known in Ireland, and both may rather be Pictish".
[4] Simon Taylor and Gilbert Márkus speculate in Place-Names of Fife that the name recorded in the annal is a Gaelic translation of an original P-Celtic name.
While it is possible that a monk called Adrian was killed by Vikings on the island, this cult is most likely a misremembering of Ethernan from a time when the Picts had ceased to function as an ethnic group within Scotland and ancient martyrdoms in Britain and Ireland were commonly attributed to Vikings.
[4] In later medieval legends, such as those recorded in the Aberdeen Breviary, Ethernan and Adrian were again treated as two entirely separate saints.