population, moulded relief decoration of pottery vessels and small figurines were produced in great quantity and often considerable quality. After moving through a late 2nd century "baroque" phase, in the 3rd century, Roman art largely abandoned, or simply became unable to produce, sculpture in the classical tradition, a change whose causes remain much discussed. Even the most important imperial monuments now showed stumpy, large-eyed figures in a harsh frontal style, in simple compositions emphasizing power at the expense of grace. The contrast is famously illustrated in the Arch of Constantine of 315 in Rome, which combines sections in the new style with roundels in the earlier full Greco-Roman style taken from elsewhere, and the Four Tetrarchs (c. 305) from the new capital of Constantinople, now in Venice. Ernst Kitzinger found in both monuments the same "stubby proportions, angular movements, an ordering of parts through symmetry and repetition and a rendering of features and drapery folds through incisions rather than modelling... The hallmark of the style wherever it appears consists of an emphatic hardness, heaviness and angularity – in short, an almost complete rejection of the classical tradition". This revolution in style shortly preceded the period in which Christianity was adopted by the Roman state and the great majority of the people, leading to the end of large religious sculpture, with large statues now only used for emperors, as in the famous fragments of a colossal acrolithic statue of Constantine, and the 4th or 5th century Colossus of Barletta. However rich Christians continued to commission reliefs for sarcophagi, as in the Sarcophagus of Junius Bassus, and very small sculpture, especially in ivory, was continued by Christians, building on the style of the consular diptych. Traditional Roman sculpture is divided into five categories: portraiture, historical relief, funerary reliefs, sarcophagi, and copies of ancient Greek works. Contrary to the belief of early archaeologists, many of these sculptures were large polychrome terra-cotta images, such as the Apollo of Veii (Villa Givlia, Rome), but the painted surface of many of them has worn away with time. Narrative reliefs While Greek sculptors traditionally illustrated military exploits through the use of mythological allegory, the Romans used a more documentary style. Roman reliefs of battle scenes, like those on the Column of Trajan, were created for the glorification of Roman might, but also provide first-hand representation of military costumes and military equipment. Trajan's column records the various Dacian