Bede's Ecclesiastical History of England, ed. by A.M. Sellar, , at sacred-texts.com
IN the meantime, the Saxons and Picts, with their united forces, made war upon the Britons, who in these straits were compelled to take up arms. In their terror thinking themselves unequal to their enemies, they implored the assistance of the holy bishops; who, hastening to them as they had promised, inspired so much confidence into these fearful people, that one would have thought they had been joined by a mighty army. Thus, by these apostolic leaders, Christ Himself commanded in their camp. The holy days of Lent were also at hand, and were rendered more sacred by the presence of the bishops, insomuch that the people being instructed by daily sermons, came together eagerly to receive the grace of baptism. For a great multitude of the army desired admission to the saving waters, and a wattled church was constructed for the Feast of the Resurrection of our Lord, and so fitted up for the army in the field as if it were in a city. Still wet with the baptismal water the troops set forth; the faith of the people was fired; and where arms had been deemed of no avail, they looked to the help of God. News reached the enemy of the manner and method of their purification, who, assured of success, as if they had to deal with an unarmed host, hastened forward with renewed eagerness. But their approach was made known by scouts. When, after the celebration of Easter, the greater part of the army, fresh from the font, began to take up arms and prepare for war, Germanus offered to be their leader. He picked out the most active, explored the country round about, and observed, in the way by which the enemy was expected, a valley encompassed by hills of moderate height. In that place he drew up his untried troops, himself acting as their general. And now a formidable host of foes drew near, visible, as they approached, to his men lying in ambush. Then, on a sudden, Germanus, bearing the standard, exhorted his men, and bade them all in a loud voice repeat his words. As the enemy advanced in all security, thinking to take them by surprise, the bishops three times cried, "Hallelujah." A universal shout of the same word followed, and the echoes from the surrounding hills gave back the cry on all sides, the enemy was panic-stricken, fearing, not only the neighbouring rocks, but even the very frame of heaven above them; and such was their terror, that their feet were not swift enough to save them. They fled in disorder, casting away their arms, and well satisfied if, even with unprotected bodies, they could escape the danger; many of them, flying headlong in their fear, were engulfed by the river which they had crossed. The Britons, without a blow, inactive spectators of the victory they had gained, beheld their vengeance complete. The scattered spoils were gathered up, and the devout soldiers rejoiced in the success which Heaven had granted them. The prelates thus triumphed over the enemy without bloodshed, and gained a victory by faith, without the aid of human force. Thus, having settled the affairs of the island, and restored tranquillity by the defeat of the invisible foes, as well as of enemies in the flesh, they prepared to return home. Their own merits, and the intercession of the blessed martyr Alban, obtained for them a calm passage, and the happy vessel restored them in peace to the desires of their people.