The mainland of Argyll, off the coast of which these islands lay, was at this time in the occupation of the Scots of Dalriada, who had now possessed these districts for upwards of forty years. Their king was Gabhran, grandson of that Feargus Mor mac Erc who had led the colony from Ireland to Scotland in the beginning of the same century. Ireland had become nominally Christian before they left its shores, and they were, in name at least, a Christian people, and, during the first sixty years of the colony, had extended themselves so far over the western districts and islands, as to bear the name of kings of Alban. Whether Tyree was at this time included in their possessions may be doubted, but Seil certainly would be. They sustained, however, a great reverse in the year 560. Brude, the son of Mailchu, whom Bede terms a most powerful monarch, became king of the northern Picts, and had his royal seat at Inverness. By him the Dalriads were attacked, driven back, and their king Gabhran slain. For the time their limits were restricted to the peninsula of Kintyre and Knapdale and probably Cowal; but the islands were lost to them.[160] This great reverse called forth the mission of Columba, commonly called _Columcille_, and led to the foundation of the monastic church in Scotland. In investigating the lives of these great fathers of the Church, and endeavouring to estimate the true character of their mission, we have to encounter a very considerable difficulty. They filled so large a space in the mind of the people, and became in consequence the subject of so much popular tradition, that the few authentic facts of their history preserved to us became overlaid with spurious matter stamped with the feelings and the prejudices of later periods; and these popular conceptions of the character and history of the saint and his work were interwoven by each of his successive biographers into their narrative of his life, till we are left with a statement of their career partly true and partly fictitious, and a false conception is thus formed of their character and mission. So it was with Patrick, the Apostle of Ireland; and Columba, the Apostle of Scotland, shared the same fate. In both cases it is necessary to separate the older and more authentic tradition from the later stratum of fable. For this purpose we possess, in the case of Patrick, his own account of himself as contained in his Confession and his epistle to Coroticus, and can test the statements of his later biographers by their consistency with these documents. In the case of Columba we have no such record to appeal to, and can only bring the narratives of the later biographers to the test of a comparison with the statements of those who wrote more near to his own time. Fortunately for us, his two earliest biographers, Cummene and Adamnan, were both his successors in the abbacy of the monastery founded by himself, and collected its traditions regarding its founder within so short a period