I was not familiar with the technique called opus sectile until I visited an exhibition in the Nieuwe Kerk in Amsterdam about Constantine’s influence on the Christianisation of the Roman Empire. Part of the exhibition was a mosaic depicting a man in a chariot and four horsemen in the colours of the circus parties, red, blue, green and white. This is not a traditional mosaic, composed of small coloured stones or pieces of glass. Rather, this work of art was made by cutting larger pieces of marble and other materials into shape and then assembling them to create a picture. Sectile refers to the process of cutting or sawing the materials.
This brightly coloured mosaic was originally part of the decoration of the so-called Basilica of Junius Bassus in Rome. It was on loan from the Palazzo Massimo in Rome, part of the Museo Nazionale Romano. We know a bit about this Junius Bassus’ life. He was obviously an important Roman nobleman, as he was consul in the year 331. His son, who was a Christian, was also called Junius Bassus. Bassus junior died in 359 and his sarcophagus is one of the most important early Christian relics of Rome. It can be found in the Treasury of Saint Peter’s Basilica in the Vatican.
The Basilica of Junius Bassus was located near the Santa Maria Maggiore. Although we usually call it a basilica – which suggests it was a public building – we cannot be certain that it actually was a basilica. The building was in any case converted into a church in the fifth century and remains of that church were demolished in 1930, so that further investigations have been made impossible. The booklet that I bought at the exhibition stated that the mosaic had been in Bassus’ fourth century residence and that it was part of the decorations of a private hall. The author of this chapter, a professor of classical archaeology, compared the hall to reception rooms found in the private residences of wealthy members of the Roman elite. The hall, later incorporated into the church of Sant’Andrea Catabarbara, measured some 21 by 12,5 metres and was about 14,5 metres high. So whatever the Basilica of Junius Bassus was – a public building, a private hall, even a funerary monument has been suggested – it was in any case a grand and richly decorated building.
In the mosaic, we see a bearded man in the centre, standing in his chariot drawn by two white horses. The perspective, especially that of the wheels of the chariot, is strange and looks unnatural. The bearded man is flanked by two horsemen on either side, representing the traditional circus parties. Although no specific location is given, the setting might be the Circus Maximus in Rome. Chariot racing continued to be popular in Christian Rome. It was an acceptable alternative to the bloody gladiatorial games in the arena. It is not clear what the men are holding in their hands. One would perhaps expect a whip, but the objects do not look like whips at all. Perhaps they are wind socks or musical instruments. The scene is open to many interpretations. It could be a procession and the man in the chariot could be the consul Junius Bassus himself. But he could just as well be someone else and the scene might simply refer to the opening of the circus games.
There was another large opus sectile mosaic in the basilica, and this can also be found in the Palazzo Massimo in Rome. Central to this mosaic is a scene depicting the ‘Rape of Hylas’. In Greek mythology, Hylas was a companion and lover of the hero Hercules (Herakles) who was abducted by nymphs. Three nymphs can be seen in the mosaic. The Rape of Hylas was a popular theme in the art of the Roman Empire, and several other examples have survived, for instance a third century mosaic from Gaul. Below the central scene is a strip with several little figurines. The style is undeniably Egyptian. Junius Bassus senior was not a Christian, unlike his son, who was a neophyte, a recent convert.
After reading a bit more about the opus sectile technique, I realised I had seen examples of it on previous visits to Rome. In fact, I had even taken pictures of these mosaics. Above is a photo of an opus sectile mosaic of a tigress attacking a calf. This mosaic and a similar one which is actually its mirror image, are in the Palazzo dei Conservatori of the Capitoline Museums in Rome. They used to be in the Basilica of Junius Bassus as well, so this basilica can rightly be seen as the treasure trove of Roman opus sectile art. Apparently the technique eventually fell out of favour and disappeared in Rome, but one can argue it was reintroduced in the medieval Cosmatesque floors that still adorn some churches in the Eternal City (the floor in the Santa Maria in Cosmedin is largely original; the one in the Santa Maria in Trastevere is a faithful copy, while the Santa Prassede has a modern Cosmatesque floor).
– Eric Moormann & Sible de Blaauw, Rome. De droom van keizer Constantijn.