In striking contrast to the continuous spiral of the column are the fine reliefs of the arch put up at Benevento (see TRIUMPHAL ARCH) , in honour of Trajan. The inscription bears the date A.D. but the prominence given in the attica to Hadrian, as well as Hellenizing traits in certain of the sculptures, have led to the supposition that the arch was not finished till after Hadrian's accession. The arrangement of the panels, which summarize Tra jan's achievements at home and abroad, is carefully calculated; on the side facing the city the subjects refer to Trajan's policy in Rome ; on the side facing the country, to his settlement of the empire. In significance, this arch is the most important monument of Roman commemorative art ; each scene, though rounded off and complete in itself, contributing to one dominating idea—the apotheosis of empire. This is consistently worked out from the picturesque relief of the passage way where the beneficent emperor is seen in the midst of grateful citizens, many of whom carry their children shoulder-high, to the grandiose panel of the attica facing towards Rome, where Jupiter offers the thunder-bolt to Trajan as supreme symbol of power, acclaiming him by this act as the princeps optimus of the inscription.
With the accession of Hadrian—the "Greekling," as he was called by writers hostile to his policy—a short-lived renaissance of classicism set in, restricted, however, to certain eclectic modi fications of Greek statuary which do not fall within our province, and to a change in the relation of background to figures in relief sculpture. The return to a background, either neutral or with the character of a drop-scene that has no organic connection with the figures, was doubtless responsible for the fact that the his torical monuments of this and the following reign often lack the pregnancy of meaning, and vigour of execution, which dis tinguish those of the Flavio-Trajanic period; mention may be made of three reliefs in the Palazzo dei Conservatori, one of which represents the apotheosis of an empress.
On the other hand, the famous hunting medallions, which were later transferred to the Arch of Constantine are vigorous and inter esting compositions, full of the rich and varied incident character istic of Rome. In portraiture the most important work of this pe riod was the idealized type of Antinous, here represented by the most exquisite of his effigies, which shows him as Silvanus (Plate II., fig. 7) and thus invests the favourite of Hadrian with a divin ity expressed in the terms of Roman art, as well as a pathos which belongs to his own time. The inscription on the altar gives us the name of Antonianus of Aphrodisias in Caria, one of a family of sculptors domiciled in Rome since the time of Trajan.
Under Marcus Aurelius and Commodus, Roman art underwent further transformation. The earliest monument of the time is the base (in the Vatican) of the column (now destroyed) erected in honour of Antoninus Pius and Faustina. The contrast is remark able between the classicistic representation of the apotheosis of the imperial pair, witnessed by the ideal figures of Roma and the Campus Martius (holding an obelisk), and the vigorous realism of the decursio, a ceremony performed by detachments of the praetorian guard on horse and foot, in which, with total disre gard of perspective as tending only to obscure the action, the artist brings all the figures into the same plane and disposes them on a few projecting ledges of equal size, a device that reappears on the column of Marcus Aurelius. The reliefs of the Aurelian column hardly suffer by comparison with the column of Trajan. We cannot, it is true, trace, as in the earlier instance, the march of events towards a dramatic climax, nor does the artist attempt to produce an impression of a chronological series of happenings. The figures are smaller and more crowded than those of the earlier column, and there is even less regard for perspective than in Trajanic art. Yet a deeper psychology informs the whole; the note of humanitas rings clear in the groups of barbarians with their women and children ; or in those scenes which centre in the person of the good and philosophic emperor; the monotony of incident is relieved by the sculptor's power of repeating the same idea in a surprising variety of ways. Many episodes are vividly treated, e.g., the famous scene of the fall of rain, ascribed in Christian tradition to the prayers of the "Thundering" Legion, the strong realism of which is in contrast to the idealism of the Hellenistic Jupiter Pluvius in a scene of the Trajan Column.