In 590, Pelagius II. died of the plague, which then depopulated Rome. Gregory was immediately elected pope by the unanimous voice of the senate, the people, and the clergy. It was in vain that he refused, and appealed to the emperor Maurice not to confirm his election. The Romans intercepted his letter; the imperial confirmation arrived. Then he disguised himself, and fleeing from Rome to seek some unknown retreat, wandered three days in the woods. He was followed, discovered, and a second time led back to Rome, but this time to reign there. He bowed his head, weeping, under the yoke imposed upon him by the Divine will and the unanimity of his fellow-citizens. It was during the interval between his election and the imperial confirmation that, filled with a paternal anxiety for the safety of the people, he organized a great procession, with solemn litanies, to seek to avert the wrath of Almighty God. It proceeded from seven stations in the city, in as many divisions, to the Church of S. Maria-Maggiore. The first company consisted of the secular clergy, the second of the abbots and their monks, the third of the abbesses and their nuns, the fourth of children, the fifth of laymen, the sixth of widows, and the seventh of matrons: each band was led by the priests of the quarter of the city from which it came. While the procession lasted, eighty persons in it died of the plague; yet S. Gregory persevered, and the prayers of the city were heard. This was the origin of the "Greater Litanies," which were afterwards held on S. Mark's Day, and which acquired the popular name of "_The Black Crosses_," from the penitential hue of the vestments and banners used therein. While the procession defiled before Gregory, he saw an angel appear upon the summit of the Mole of Hadrian, putting back his sword into its sheath, the image of which, standing upon the colossal mausoleum, has given its name to the castle of S. Angelo, and perpetuated to our day the recollection of S. Gregory's vision.