Tertullian

Tertullian trained as a lawyer in Carthage before converting to Christianity as an adult, and he wrote like one: forensic, combative, allergic to hedging. He gave Latin Christianity most of its vocabulary — trinitas, persona, substantia — words a later council would need when it tried to explain how one God could be three. His Apology argued that persecuting Christians for their faith alone, without evidence of any crime, was a legal absurdity, and that the blood of martyrs was seed: every execution made more converts than it silenced. He turned against Greek philosophy as a corrupting influence on faith, asking what Athens had to do with Jerusalem, and meant it as a real either/or. In middle age he joined the New Prophecy movement, a rigorist sect that expected the world to end soon and had no patience for a church growing comfortable with the empire. The mainstream church he had once defended eventually treated him as a heretic. He never recanted. What survived was not his standing but his sentences — blunt, quotable, built to convince a hostile court.