I was recently reading Marcus Aurelius Antoninus and his position on the Christian problem, and in some ways it struck me that the guarded position of the state at that time is possibly not too different from how states today view Islamic minorities in the West - as potential sources of trouble.
This led me to wonder if there were any Christian (Christianist? Christian fundamentalist?) groups which engaged in violence against the Roman Empire and its citizens to gain political concessions. Were there Christian terrorists at that time? Did people sympathise with them? Would you be labelled a Christianophobe for fearing the rise of Christianity?
Cheers for any insights!
No, there were not. There were not incidents or movements of 'terrorism' against the Roman 'state'. (Strictly speaking, both those terms are a bit anachronistic).
Early Christianity, prior to Constantine, was strongly opposed to killing in general. This is borne out by no theological writer condoning military service for Christians, for the twin reasons that armed service involved idolatry, and the general prohibition against killing. There is some small epigraphic evidence that nonetheless some soldiers were Christians, pre-Constantine, and certainly from Constantine's conversion onwards there were growing numbers of Christian soldiers.
I realise you are not asking about Christians in the Roman military, but I am addressing a broader question for you, which is that Christians were overwhelmingly opposed to killing. This includes not only state-sanctioned military service, but even more so 'terrorism' against the Roman political apparatus.
There has been debate among historians and authors recently over whether this opposition was a consensus, or in fact a contested view. Sider's volume (The Early Church on Killing: A Comprehensive Sourcebook on War, Abortion, and Capital Punishment) is a great resource if you want to wade through primary sources in translation on the topic of early Christian attitudes to killing.