In 590, when he was elected Pope, the city of Rome was suffering from a dreadful pestilence: the people were dying by thousands; out of one procession imploring the mercy of Heaven no less than eighty persons died within an hour: what the heathen in an earlier epoch had attributed to Apollo was now attributed to Jehovah, and chroniclers tell us that fiery darts were seen flung from heaven into the devoted city.

But finally, in the midst of all this horror, Gregory, at the head of a penitential procession, saw hovering over the mausoleum of Hadrian the figure of the archangel Michael, who was just sheathing a flaming sword, while three angels were heard chanting the Regina Coeli.

The legend continues that the Pope immediately broke forth into hallelujahs for this sign that the plague was stayed, and, as it shortly afterward became less severe, a chapel was built at the summit of the mausoleum and dedicated to St.Michael; still later, above the whole was erected the colossal statue of the archangel sheathing his sword, which still stands to perpetuate the legend.

Thus the greatest of Rome's ancient funeral monuments was made to bear testimony to this medieval belief; the mausoleum of Hadrian became the castle of St.Angelo.A legend like this, claiming to date from the greatest of the early popes, and vouched for by such an imposing monument, had undoubtedly a marked effect upon the dominant theology throughout Europe, which was constantly developing a great body of thought regarding the agencies by which the Divine wrath might be averted.
First among these agencies, naturally, were evidences of devotion, especially gifts of land, money, or privileges to churches, monasteries, and shrines--the seats of fetiches which it was supposed had wrought cures or might work them.

The whole evolution of modern history, not only ecclesiastical but civil, has been largely affected by the wealth transferred to the clergy at such periods.