Such is a short view of the character of the monastic system established by Columba in the island of Iona. It presented the same life of strict submission to a rule enforcing observance of religious duty, ascetic practice and self-denial, which characterised the monastic church in Ireland, and its doctrines in no respect differed from those of that church. Their doctrinal system was that common to the Western Church prior to the fifth century, and it is pervaded by the ecclesiastical language of that early period. The divergence which took place between the Irish and the Roman Churches related to points of doctrine, or matters of observance, which emerged in the Western Church after that date, when all intercourse between it and the Churches of Britain and Ireland, beyond the bounds of the Roman empire, had been for the time interrupted; and to the authority of the Church of Rome with regard to such matters of faith and practice, when they again came into contact, the Columban Church, in common with the Irish Church, opposed the custom of their fathers, for which they claimed the sanction of the second general council, held in the year 381. To use the language of Columbanus, the Columban Church ‘received nought but the doctrine of the evangelists and apostles;’ and, as we learn from Adamnan, the foundation of Columba’s preaching, and his great instrument in the conversion of the heathen, was the Word of God.[202] [Sidenote: St. Columba’s labours among the Picts.] Such then was the form in which, in the monastery founded by him in the island of Iona, Columba exhibited the Christian life to the surrounding heathen, and such the spirit in which he proceeded to do battle with the paganism which confronted him. Directly facing him to the east was the great pagan nation of the northern Picts, occupying the whole of Scotland north of the great range of the Mounth, and extending from sea to sea. Immediately before him, separated from Iona by a narrow channel, was the large island of Mull, with its low flat promontory stretching out towards the island; and behind it, on the mainland, extended the western districts of Ardnamurchan, Morven, and Lochaber, separated from the main body of the Pictish kingdom by the western part of the range of Drumalban, that part of it which was situated south of the Mounth forming the eastern boundary of the Scottish kingdom of Dalriada.