Such were the objects of interest and grandeur that met the eye as it was turned toward the various quarters of the city, which contained between three and four millions of people.  Lipsius estimates four millions as the population, including slaves, women, children, and strangers.  Though this estimate is regarded as too large by Merivale and others, yet how enormous must have been the number of the people when there were nine thousand and twenty-five baths, and when those of Diocletian could accommodate thirty-two hundred bathers at a time!  The wooden theatre of Scaurus contained eighty thousand seats; that of Marcellus twenty thousand; the Colosseum would seat eighty-seven thousand persons, and give standing space for twenty-two thousand more.  The Circus Maximus would hold three hundred and eighty-five thousand spectators.  If only one person out of four of the free population witnessed the games and spectacles at a time, we thus must have four millions of people altogether in the city.  The Aurelian walls are now only thirteen miles in circumference, but Lipsius estimates the original circumference at forty-five miles, and Vopiscus at nearly fifty.  The diameter of the city must have been eleven miles, since Strabo tells us that the actual limit of Rome was at a place between the fifth and sixth milestone from the column of Trajan in the Forum,—­the central and most conspicuous object in the city except the capitol.

Modern writers, taking London and Paris for their measure of material civilization, seem unwilling to admit that Rome could have reached such a pitch of glory and wealth and power.  To him who stands within the narrow limits of the Forum, as it now appears, it seems incredible that it could have been the centre of a much larger city than Europe can now boast of.  Grave historians are loath to compromise their dignity and character for truth by admitting statements which seem, to men of limited views, to be fabulous, and which transcend modern experience.  But we should remember that most of the monuments of ancient Rome have entirely disappeared.  Nothing remains of the Palace of the Caesars, which nearly covered the Palatine Hill; little of the fora which, connected together, covered a space twice as large as that inclosed by the palaces of the Louvre and Tuileries, with all their galleries and courts; almost nothing of the glories of the Capitoline Hill; and little comparatively of those Thermae which were a mile in circuit.  But what does remain attests an unparalleled grandeur,—­the broken pillars of the Forum; the lofty columns of Trajan and Marcus Aurelius; the Pantheon, lifting its spacious dome two hundred feet into the air; the mere vestibule of the Baths of Agrippa; the triumphal arches of Titus and Trajan and Constantine; the bridges which span the Tiber; the aqueducts which cross the Campagna; the Cloaca Maxima, which drained the marshes and lakes of the infant city; and, above all, the Colosseum.  What glory and shame are associated with that single