The first secular buildings which attained monumental importance were undoubtedly those erected for public usefulness, like the extensive covered canals so requisite to the very existence of Rome. On the one hand, it was necessary, by means of gigantic sewers, to drain the low land, which was not only full of springs, but was periodically flooded by the Tiber; on the other, to provide the metropolis with good water by aqueducts extending to great distances. Still, it was not until the year 312 B.C., more than two centuries after the building of the Cloaca Maxima, that the first work of this kind, the Aqua Appia, was completed, simultaneously with the first great military road, by the famous censor Appius Claudius Cæcus. This entirely subterranean aqueduct, eight Roman miles long, was followed, down to the time of Diocletian, by no less than thirteen similar constructions of increased dimensions and magnificence. (Fig. 274.) Almost all extended to the mountains which surround the Campagna, even reaching a length of forty-two Roman miles. They provided so great a quantity of excellent water that one third part of it would have been more than sufficient for the real necessities of the city. Stupendous arches raised the conduits high above the ground, while valleys and ravines were spanned by mighty works of engineering, even rivalling the bridges upon the great military roads. The greater part of the water thus obtained was used for the baths, which were increased under the emperors to a measureless luxury, and provided the chief means by which these rulers purchased the favor of the populace. There were in Rome no less than eight hundred and fifty-six private baths open to the use of every citizen for a certain price, besides the great imperial structures which were free to the public. The first founder of these free baths was Agrippa, in 25 B.C., who appears to have followed, in their general arrangement, the type of a Greek gymnasion. The bodily exercises of early times, by which the military power of the State had been trained, were succeeded under the empire by a luxurious care for physical well-being; gymnastic drill appeared unnecessary to the sovereigns of all the known world, while the bath and the toilet became more and more important. Thus, in the Roman baths, the spaces for serious athletic contests, which had formed the principal part of the Greek gymnasion, were wholly subordinated to the departments for indolent luxury and light amusements. The primitive bathing-chambers were enlarged to magnificent halls, which offered the greatest scope for the development of that interior architecture which was cultivated with such great success by the Romans. This grandeur is evident in the imposing rotunda still remaining from the Baths of Agrippa, the remarkable circular structure which, because of its beauty, was transformed by Agrippa himself into a temple—the Pantheon—by the addition of Corinthian columns. (Figs. 275 and 276.) The building, not having been originally planned for an isolated position, is wholly undeveloped upon the exterior, but its massive construction and harmonious proportions have merited the admiration accorded to it in all ages. From the existing remains it cannot be surely determined whether the Baths of Nero, Titus, Trajan, and Commodus, which followed the great creation of Agrippa, surpassed it in dimensions and magnificence; but it is certain that this was the case with the enormous structures of Caracalla and of Diocletian, as the entire plan of the former, with parts of the mosaic pavements, still remains; while the main hall of the latter, in almost perfect preservation, forms the chief part of the Church of S. Maria degli Angeli. The principal structure was usually surrounded by an extensive enclosure, which, in the case of the Baths of Caracalla (Fig. 277), was formed upon the front (a) by a series of separate cabinets. Upon the sides were segmental projections, or exedras (b), with various chambers (c), probably intended for intellectual entertainments, such as rhetorical and poetical dissertations, etc.; while the rectangle was closed by a one-sided stadion, with spaces for gymnastic purposes (d), and a reservoir for water (e). The central building provided upon either side enormous halls for games, preparatory to the ablutions (g, p), between them (i, k, l) the spaces for the cold, tepid, and hot baths; while the adjoining smaller chambers served as rooms for dressing and the manifold processes of the toilet. Between this chief structure and the enclosure race-courses and promenades, with fountains and beds of flowers, added the charms of nature to the magnificence of architecture. The public Baths of Alexander Severus, Decius, and Constantine appear to have been less extended; but these were far surpassed in size by the constructions of Diocletian, which could accommodate three thousand bathers. The Roman buildings for the circus, the theatres, and amphitheatres were of scarcely less importance. The extreme simplicity of the Circus Maximus recalls the early Greek hippodrome; the slopes of the Palatine and Aventine served as a station for the spectators, while the level ground in the valley between formed the arena. It was not until 327 B. C. that the barriers (carceres) were architecturally embellished, and even the rebuilding of the whole by Cæsar was limited to the erection of the lower stories of the auditorium in stone. The wooden superstructure was not replaced by a more permanent and monumental construction until the time of Domitian and Trajan. The general plan was adopted from the Greek model, the peculiarities of the Roman arrangement being a low division wall, or spina, the position of the barriers, and the moat which surrounded the arena (euripis), intended to protect the lower tiers of spectators during the combats of wild beasts. The spina, connecting the two turning-posts (metæ), was ornamented with memorial columns, altars, ædiculas, statues, obelisks, and the like; it did not follow a direction precisely parallel to the side seats, but allowed a considerably broader space upon the right than upon the left, so that the many chariots here crowded together early in the race might not be too greatly impeded. That all the competitors might have an equally favorable position when brought into line, it was necessary that the starting-points should be arranged in the segment of a circle, the centre of which was a little to the right of the spina. This plan may be recognized in the best-preserved Roman circuses, as, for instance, in that at Bovillæ, near Albano, and that of Romulus, the son of Maxentius, upon the Via Appia. (Fig. 279.) The Circus Maximus, like all the other structures of its kind in Rome, has been entirely destroyed.
In the earlier periods of Roman history, the theatre did not receive the recognition and assistance of the government; and the law in force until the end of the republic, which permitted no theatre with seats to be constructed within the limits of the city, prevented any monumental development in this direction. Dramatic representations, however, were not to be suppressed after an acquaintance with the Greek drama had once been formed. Comedy was especially popular, and Roman authors devoted their attention to it with success. But these plays were performed only upon festival days, and were undertaken by individuals. The creation of the improvised stage, for transient usage, thus fell to the lot of those politicians whose desire it was to win the favor of the populace. In the latter days of the republic structures were reared which equalled the extravagant magnificence of the Diadochi; the ædile M. Scaurus, for instance, erected a gigantic theatre, to stand only a few days, which provided seats for no less than eighty thousand spectators, the stage being ornamented by three hundred and sixty marble columns and three thousand bronze statues. This boundless waste was brought to an end through the building of the first stone theatre in Rome, by Pompey, who, notwithstanding his great political power, could succeed in silencing the objections made by the conservative party against this innovation only by the pretence that the stone seats were the steps of a temple, which he erected upon the summit of the cavea. This first permanent structure was succeeded during the reign of Augustus by two other theatres, those of Marcellus and of Balbus; the first could seat but a quarter as many spectators as did the theatre of Pompey—namely, twenty thousand—while that of Balbus provided places for only eleven thousand six hundred. In later imperial times even this capacity was found too great. The theatre lost much of its attraction after the Roman people had once seen blood flow in the arena. Yet in all the Roman empire there was scarcely a city of importance where a stone theatre was not erected during the reign of Augustus; even small towns like Tusculum, where the remains are particularly well preserved, boasted of these monuments. The characteristic differences between the Roman theatre and the Greek, its prototype, were that the orchestra did not exceed a semicircle, the front of the stage (A A) being so advanced as to form its diameter, which thus brought the actors nearer to the spectators. (Fig. 280.) The open half of the circle was not, as in Greece, reserved for the evolutions of the chorus, but was occupied by the senators and the higher classes of citizens, who brought thither their own seats. The auditorium, which, with the orchestra, had been restricted to a semicircle, assumed a peculiar form upon the exterior, the entire building standing in a plain, and only rarely, as in Tusculum, occupying a natural slope. With the introduction of vaulting, massive foundations of masonry were rendered unnecessary. Barrel vaults were placed one above another, terminating upon the exterior in a series of arcades, the decorative features of Roman architecture being usually so applied that the lower story displayed engaged Tuscan columns, the second Ionic, and the third Corinthian pilasters, with their respective entablatures. This treatment of the exterior is shown in the best preservation by the remaining amphitheatres; but vestiges of theatres may still be seen sufficient to serve as illustrations, like that of Marcellus (Fig. 281), and those at Orange in Southern France, at Aspendos in Asia Minor, etc.
