angel that was seen to hover over the
Mausoleum of Hadrian, while Gregory was passing it in solemn
procession, and to sheathe his flaming sword as a sign that the
pestilence was about to cease. At the same time three angels were
heard to sing the antiphony _Regina Coeli_, to which Gregory replied
with the hymn _Ora pro nobis Deum alleluja!_"[110]

This graceful story is the invention of a later century, but it is
worth while to trace its origin. It was customary in the Middle Ages
to consecrate the summits of hills and mountains to Michael, the
archangel, from an association of ideas which needs no explanation.
Similarly, in classical times, the Alpine passes had been placed
under the protection of Jupiter the Thunderer, and lofty peaks crowned
with his temples. Without citing the examples of Mont Saint Michel on
the coast of Normandy, or of Monte Gargano on the coast of Apulia, we
need only look around the neighborhood of Rome to find the figure of
the angel wherever a solitary hill or a commanding ruin suggested the
idea or the sensation of height. _Deus in altis habitat._ Here is the
isolated cone of Castel Giubileo on the Via Salaria (a fortified
outpost of Fidenae); there the mountain of S. Angelo above Nomentum,
and the convent of S. Michele on the peak of Corniculum. The highest
point within the walls of Rome, now occupied by the Villa Aurelia
(Heyland) was covered likewise by a church named S. Angelo in
Janiculo. The two principal ruins in the valley of the Tiber--the
Mausoleum of Augustus and that of Hadrian--were also shaded by the
angel's wings. The shrine over the vault of the Julian emperors was
called S. Angelo de Augusto, while that built by Boniface IV.
(608-615) above Hadrian's tomb was called _inter nubes_ (among the
clouds), or _inter coelos_ (in the heavens). This shrine was
replaced later by the figure of an angel. During the pestilence of
1348 the statue was reported by thirty witnesses to have bowed to the
image of the Virgin which the panic-stricken people were carrying from
the church of Ara Coeli to S. Peter's. In 1378 the ungrateful crowd
destroyed it in their attempt to storm the castle. Nicholas V.
(1447-1455) placed a new image on the top of the monument, which
perished in the explosion of the powder-magazine in 1497. The shock
was so violent that pieces of the statue were found beyond S. Maria
Maggiore, a distance of a mile and a half. Alexander VI., Borgia, set
up a statue for the third