The Ecclesiastical History of Sozomen

The failure which had attended the designs of Attalus was a source of deep displeasure the pagans and Christians of the Arian heresy. The pagans had inferred from the known predilections and early education of Attalus, that he would openly maintain their superstitions, and restore their ancient temples, their festivals, and their altars. The Arians imagined that, as soon as he found his reign firmly established, Attalus would reinstate them in the supremacy over the churches which they had enjoyed during the reigns of Constantius and of Valens; for he had been baptized by Sigesarius, bishop of the Goths, to the great satisfaction of Alaric and the Arian party.

Soon after, Alaric stationed himself among the Alps, at a distance of about sixty stadia from Ravenna, and held a conference with the emperor concerning the conclusion of a peace. Saros, a barbarian by birth, and highly practiced in the art of war, had only about three hundred men with him, but all well disposed and most efficient. He was suspicious of Alaric on account of their former enmity, and reasoned that a treaty between the Romans and Goths would be of no advantage to him. Suddenly advancing with his own troops, he slew some of the barbarians. Impelled by rage and terror at this incident, Alaric retraced his steps, and returned to Rome, and took it by treachery. He permitted each of his followers to seize as much of the wealth of the Romans as he was able, and to plunder all the houses; but from respect towards the Apostle Peter, he commanded that the large and very spacious church erected around his tomb should be an asylum. This was the only cause which prevented the entire demolition of Rome; and those who were there saved, and they were many, rebuilt the city.