All that is left of Celsus (SEHL-suhs) is his influential anti-Christian polemic entitled Alīthīs Logos (probably between 175 and 181 c.e.; On the True Doctrine, 1987, translated from pieces preserved in the reply written by the Christian writer Origen). Though this work is more emotive than philosophic, it nevertheless suggests an author who was highly educated, particularly in Middle Platonic thought. Portions of this work are reminiscent of philosopher Lucian’s satirical portrayal of the charlatan Peregrinus, and the author also exhibits a good knowledge of second century Judaic and Christian perspectives. Celsus probably wrote his polemic during the reign of Marcus Aurelius (r. 161-180 c.e.), a period of military and social troubles that marked the end of the Pax Romana. Indeed, he may have written this polemic for the emperor himself in an effort to encourage persecution of the Christians.
The central theme of this work was that Christians had irrationally abandoned all ancient traditions, creating a novel religion that worshiped a magician and condemned criminal. For Celsus, these cultural rebels represented the worst elements of ignorance and disorder. He understood that Christians had already been divided by heresies and was astounded at their negative attitudes regarding the ancient pagan divinities. Celsus also found hypocritical their apparent disdain for the same Judaic traditions from which they claimed descent. In the end, he wrote to admonish these rebels for their rejection of the traditions that had made Rome strong.