That assault was not, however, begun by Ireland; it was begun, as every one knows, by St. Augustine, a Roman priest, sent by Pope Gregory, who landed at Ebbsfleet, in the Isle of Thanet, in the year 597--thirty-two years after St. Columba left Ireland. If the South of England owes its conversion to Rome, Northern England owes its conversion to Ireland, through the Irish colony at Iona. Oswald, the king of Northumbria, had himself taken refuge in Iona in his youth, and when summoned to reign he at once called in the Irish missionaries, acting himself, we are told, as their interpreter. His whole reign was one continuous struggle with heathenism, and although at his death it triumphed for a time, in the end the faith and energies of the missionaries carried all before them. After the final defeat of the Mercians, under their king Penda, at Winwoed, in 655, the struggle was practically over. Northern and Southern England were alike once more Christian. One of the chief agents in this result was the Irish monk Aidan, who had fixed his seat in the little peninsula of Lindisfarne, and from whose monastery, as from another Iona, missionaries poured over the North of England. At Lichfield, Whitby, and many other places religious houses sprang up, all owing their allegiance to Lindisfarne, and through it to Iona and Ireland. In this very fervour there lay the seeds of a new trouble. A serious schism arose between Western Christendom and the Papacy. Rome, whether spiritually or temporally, was a name which reverberated with less awe-inspiring sound in the ears of Irishmen (even Irish Churchmen) than, probably, in those of any other people at that time on the globe. They had never come under the tremendous sway of its material power, and until centuries after this period--when political and, so to speak, accidental causes drove them into its arms--its spiritual power remained to them a thing apart, a foreign element to which they gave at most a reluctant half adhesion. From this it came about that early in the history of the Western Church serious divisions sprang up between it and the other churches, already being fast welded together into a coherent body under the yoke and discipline of Rome. The points in dispute do not strike us now of any very vital importance. They were not matters of creed at all, merely of external rule and discipline. A vehement controversy as to the proper form of the tonsure, another as to the correct day for Easter, raged for more than a century with much heat on either side; those churches which owed their allegiance to Iona clinging to the Irish methods, those who adhered to Rome vindicating its supreme and paramount authority.