In The Myth of Persecution, Candida Moss reveals that the “Age of Martyrs” is a fiction—there was no sustained three-hundred-year-long effort by the Romans to persecute Christians.
I’m not sure why Moss sees a need to argue against “systematic persecution” or a “sustained three-hundred-year-long effort” of persecution, since no one studying Christianity in the Roman Empire that I know of argues that this is what happened. If there is one thing we do know about Roman persecutions of Christians, it is that they weren’t systematic and they weren’t sustained. I doubt that anyone seriously defends or teaches the idea that there was a constant, universal Roman policy of persecution that never let up, and anyone who does teach such a thing knows virtually nothing about the history of the church or the Roman Empire.
The persecutions tended to be relatively brief, sporadic, ad hoc, and reactionary moves by specific emperors, and they were irregularly enforced and the length and severity of enforcement typically depended on the attitudes of the local officials. The persecutions created deep divisions within the Christian communities affected by them, which split along the lines of those that were seen as having compromised with the persecutors and those that resisted. This is why groups such as the Novatians and Donatists came into existence. Of course there were people killed for their Christian faith during these persecutions, so in the most important sense stories about the persecutions are not made up. Are martyrological texts stylized and not always reliable historical sources? Well, yes, but then this is hardly news to anyone who works with or reads ancient historical materials. It doesn’t mean that most of the martyrs around whom these stories were being made never existed or that they didn’t suffer persecution and death.