 This line of argument was often put forward by early Christians, most notably Christian apologist Tertullian, to defend their freedom to practice their cult in a time where they were persecuted by Roman governors: their claim was that forcing them to abandon the Christian cults would have no effect on their conscience. The same line of argument can also be found in Locke’s works on toleration, the Essay Concerning Toleration of 1667 and A Letter Concerning Toleration of 1689.