 In accordance with Augustine’s view of warfare, Christians were entitled to ask the Roman authorities, including those among them who were Christian, for military protection against the violence of heretics and anti-Christians. But it was a further step to ask the authorities to coerce heretics to convert them to orthodox  Christianity.[16]  At first Augustine disapproved of such coercion: “A man cannot believe unless he is willing”  (Tractates on the Gospel of John, XXVI.2).  But after a while he was persuaded and became an advocate of the use of force to “compel them to come in”  (Luke 14:16–24).[17]  He was persuaded by converted Donatists who expressed gratitude to those who had compelled them to convert  (Letter 93 V.17–19).