The Crisis of the Centurion's Oath
The defining episode of Marinus's life is the dispute over his promotion. He had served capably and was about to receive the rank of centurion when a competitor for the same post raised an objection: under ancient law, the holder of such Roman office was required to offer sacrifice to the emperor, and Marinus, as a Christian who would not sacrifice, was therefore ineligible.
Until this moment Marinus had kept his Christian faith secret. The challenge forced the question into the open, and he professed his faith plainly, explaining that it prevented him from making the demanded sacrifice. The matter thus turned on the conflict between Roman civic-religious duty and Christian confession that lay at the heart of the pre-Nicene persecutions.