This successor was Oswald, who came from Iona evidently determined to play the part of a Christian hero-king, and who endured to his life’s end steadfast in that decision. By one bold stroke he delivered his nation, Bernicia, from the Cambrian ravagers. “When he arrived after the death of his brother Eanfrid with a small army, and fortified by the faith of Christ, the wicked general of the Britons with the immense forces which, as he boasted, nothing could resist, was slain by him at the place which is called in the English tongue Denisesburn,’ that is, the stream of Denis.” So runs the first simple statement of Bede as to this important encounter which for ever settled the question whether the Celt or the Teuton was to be supreme in Northern Britain. From Bede himself, as a kind of afterthought, and from Adamnan, the biographer of St. Columba, we get some additional particulars which enable us to see more clearly if not the strategic features of the battle at least what was passing in the minds of the combatants. It seems that the battle itself was fought not at “Denisesburn” but at Heavenfield, a little on the north of the Roman wall, which probably was an important element in the problem that the Anglian king, with his great inferiority of forces, had to solve.[63] The great Roman work, striding across the country in its uncompromising way, here traverses a high moorland which separates the main stream of the Tyne from its northern affluent, and in this portion of its career it is from 700 to 800 feet above the level of the sea. Though none of its stones are here remaining, we can yet trace the high mounds and deep fosses of its companion, the line of fortification on the south, which is known by the name of the _vallum_. Between these two lines, that of stone and that of earth, ran the Roman road, still probably in Edwin’s day capable of being traversed, notwithstanding 230 years of neglect. Along this road Cadwallon may have marched, and by it he may have encamped for the night, while somewhere, behind either wall or _vallum_, Oswald may have placed in ambush his father’s veterans. He himself was in a mood of religious and patriotic exaltation. On the day before the battle he had in his sleep a vision of the blessed Columba, whom he had never seen with the eyes of the flesh. The saint’s beautiful face shone with angelic brightness: his figure rose majestic till it seemed to touch the clouds: he spread his mantle over the Anglian camp. Addressing Oswald in the words which Moses spake to Joshua he told him to be strong and of a good courage, for the Lord would be with him. Let him march out on the following night to battle: his foes should be all scattered in flight, and the Welsh king should be delivered into his hands.