Gaius was a Christian writer who lived in Rome at the end of the 2nd century CE. The only details about his life come from Eusebius of Caesarea, who betrays his own great esteem for Gaius. At first he characterizes him as ἐκκλησιαστικὸς ἀνήρ (Eus. Hist. eccl. 2.25.6), an expression that – in Eusebius’ terminology – is used to indicate one’s orthodoxy above all; later he calls him λογιώτατος (Hist. eccl. 6.203, “very erudite”). Eusebius places him at Rome during Zephyrinus’ pontificate (199–217 CE) and says that Gaius wrote a Dialogue against P…