Leithart describes in chapter one of Defending Constantine the horrors of Christian persecution. These Christians were tortured in the most brutal form because they refused to sacrifice to the pagan gods under Diocletian (22). One particularly gruesome example is of a Christian named Peter.
(He) refused to comply with the order of sacrifice. Soldiers stripped him, hoisted him naked, and whipped him until his body was a bloody pulp, his bones sticking through the flesh and skin. Still he refused to sacrifice. The soldiers brought vinegar and salt from the mess and poured it over his wounds. Finding raw meat unappetizing, even when spiced up, they decided to cook him, slowly roasting parts of his body while trying to keep him alive. He was still refusing to sacrifice when he died.