But it is ever the darkest hour that precedes the dawn. It was impossible that England should lose her faith and fall back under the rule of a mere heathen conqueror. After the "thoughtful Edwin, mightiest of all the kings of the isle of Britain," as he has been called (he was, by the way, the founder of Edinburgh), there arose another champion of the new light in the person of Oswald, Edwin's nephew. Oswald's history connects him with Columba the Irishman, and "Apostle of Scotland," to whose splendid work the nation owed its first real religious advance. About 563, when in his forty-second year, and accompanied by twelve companions, Columba found a resting-place on the little island of Hy or Iona, off the west coast of Scotland, whence he set himself to the great work of his life--the conversion of the Pictish tribes beyond the Grampians. At Iona Oswald had sheltered during the home troubles, and many valuable lessons he must have learned for the strenuous life that lay in front of him. Called to lead his countrymen against their oppressors, Oswald literally fought his way to the throne. On a rising ground, a few miles from Hexham, near the Roman Wall, he gathered in 634 a small force, which pledged itself to become Christian if it conquered in the engagement. Causing a cross of wood to be hastily made, and digging a hole for it in the earth, he supported it with his own hands while his men hedged up the soil around it. Then, like Bruce at Bannockburn years afterwards, he bade his soldiers kneel with him and entreat the true and living God to defend their cause, which he knew to be just, from the fierce and boastful foe. This done they joined battle, and attacked Cadwallon's far superior forces. The charge was irresistible. The Welsh army fled down the slope towards the Deniseburn,--a brook near Dilston which has been identified with the Rowley Burn,--and Cadwallon himself, the hero of fourteen battles and sixty skirmishes, was caught and slain. This was the battle of Hefenfelt, or Heaven's Field, as after-times called it. Not only was the last hero of the old British races utterly routed, but Oswald, King of once more reunited Bernicia and Deira, proved himself to the Christian cause all that Edwin had been, and more, a prince in the prime of life, and fitted by his many good qualities to attract a general enthusiasm of admiration, reverence, and love. Resolved to restore the national Christianity, and to realize the ambitions of his exile life, he turned naturally to Iona and to the teachers of his youth for missionaries who would accomplish the holy task. At his request, Aidan, one of the fittest of the Columban band, was sent to carry on the work of evangelization in Northumbria, which happy event may be reckoned as the first permanent planting of the Gospel in the Eastern Border. The light which he kindled was never afterwards quenched. And as Columba had chosen Iona, so for Aidan there was one spot to which his heart went out