During the Roman empire there were two different kinds of iconoclasm. Broadly speaking, these can be termed secular and religious iconoclasm, but the spheres of religion and politics were closely intertwined in antiquity. For that reason, the separation between the two cannot be made so easily, and must be treated with some caution. I will, however, in my thesis be focusing on what can be termed religious iconoclasm, and specifically early Christian iconoclasm, i.e. the destruction of pagan images by Christians.
The best known form of (‘secular’) iconoclasm is probably the practice of damnatio memoriae (although it was never called that by the Romans), meaning the action of destroying a person’s likeness to erase his memory from history. There is both good literary and archaeological evidence for this, which Eric R. Varner has compiled in an exhaustive catalogue (see reference). Many ‘bad’ emperors suffered this fate, including Caligula (37-41 CE), who was the first one. Sometimes portraits were altered rather than destroyed, such as the example below, a portrait of Gaius Caligula that has been transformed into the Forbes type of Augustus:
A portrait of Augustus in the Ny Carlsberg Glyptotek, Copenhagen. Photo: TMK, 2002.
And then there’s religious iconoclasm, the main topic of my thesis. The earliest archaeologically documented example (from the Roman period) that I’ve found so far goes back to the time of the persecutions against the Bacchus cult in the 2nd century BCE. A terracotta throne found in Volsinii with bacchic motives was probably the victim of such an iconoclastic attack. This was one of several cults that were targeted in the Republican period. The Isis cult, for example, was outlawed and its priests exiled several times because of its ‘foreign’ elements.
This also goes to show that the idea that Christians were especially targeted is a myth. In the 2nd and 3rd century CE, they were targeted because of their number and refusal to recognize the imperial powers.