reflection must be applied to the
three last ages; and we should vainly seek the Septizonium of Severus,
which is celebrated by Petrarch and the antiquarians of the sixteenth
century. While the Roman edifices were still entire, the first blows,
however weighty and impetuous, were resisted by the solidity of the mass
and the harmony of the parts; but the slightest touch would precipitate
the fragments of arches and columns that already nodded to their fall.

After a diligent inquiry, I can discern four principal causes of the
ruin of Rome, which continued to operate in a period of more than a
thousand years. I. The injuries of time and nature. II. The hostile
attacks of the Barbarians and Christians. III. The use and abuse of the
materials. And IV. The domestic quarrels of the Romans.

I. The art of man is able to construct monuments far more permanent than
the narrow span of his own existence; yet these monuments, like himself,
are perishable and frail; and in the boundless annals of time his life
and his labors must equally be measured as a fleeting moment. Of a
simple and solid edifice it is not easy, however, to circumscribe the
duration. As the wonders of ancient days, the Pyramids attracted the
curiosity of the ancients: a hundred generations, the leaves of autumn,
have dropped into the grave; and after the fall of the Pharaohs and
Ptolemies, the Caesars and caliphs, the same Pyramids stand erect and
unshaken above the floods of the Nile. A complex figure of various and
minute parts is more accessible to injury and decay; and the silent
lapse of time is often accelerated by hurricanes and earthquakes, by
fires and inundations. The air and earth have doubtless been shaken, and
the lofty turrets of Rome have tottered from their foundations, but the
seven hills do not appear to be placed on the great cavities of the
globe; nor has the city in any age been exposed to the convulsions of
nature which in the climate of Antioch, Lisbon, or Lima, have crumbled
in a few moments the works of ages in the dust. Fire is the most
powerful agent of life and death: the rapid mischief may be kindled and
propagated by the industry or negligence of mankind; and every period of
the Roman annals is marked by the repetition of similar calamities. A
memorable conflagration, the guilt or misfortune of Nero's reign,
continued, though with unequal fury, either six or nine days.
Innumerable buildings, crowded in close and crooked streets, su