The Procession of St. Gregory
Location: Basilica of St. Peter in Chains, Rome, Italy
In 590 the newly elected Pope Gregory I called on the entire populace to process from their seven regions to Santa Maria Maggiore in solemn prayer for pardon and an end to the plagues that had beset the city for almost fifty years. A legend has it that St. Michael the Archangel ended the plague, stood atop the mausoleum of Hadrian, and sheathed his sword to show that the people's prayers had been answered.
The painting seeks to hit all the main points of the story. In the hall at the top of the stairs, Gregory orders the procession. At the foot of the stairs, to the left, we see the multitudinous procession led by the Pope. To the right, St. Michael drives away a devil representing the plague, whose victims are piled up in the lower right corner. Finally, we see at the very top of the mausoleum the statue of St. Michael that is there to this day. (Ever since, the mausoleum has been known as Castel Sant'Angelo, the "Castle" of the "Holy Angel" St. Michael.)
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More of Pope Gregory I
Sources: Photographed at the site by Claire Stracke, shared under Attribution-NonCommercial-ShareAlike license. Historical information from the Catholic Encyclopedia, s.v. "Pope St. Gregory I."