Origen's eight-book, point-by-point refutation of the pagan philosopher Celsus's attack on Christianity, written around 248 CE at the request of his patron Ambrose.
Against Celsus (Contra Celsum) is Origen of Alexandria's massive rebuttal of a lost work called The True Word, written by the second-century Greek philosopher Celsus. Because Origen quotes Celsus extensively in order to answer him, his treatise is also the main surviving source for what pagan intellectuals actually said against Christianity in its first two centuries. Origen structures the whole work as a running dialogue: he restates a charge from Celsus, then answers it, book after book, without much independent organization beyond following his opponent's original sequence.
The charges Origen answers are wide-ranging: that Christianity is a secret society bound together like a conspiracy, that Jesus's miracles were common magician's tricks, that his birth from a virgin was a cover story for an affair (Celsus reports a rumor that Jesus's real father was a Roman soldier named Panthera), that the resurrection appearances were hallucinations or lies, that Christian teaching is intellectually crude and aimed at the ignorant, and that Christians borrowed and garbled Greek philosophy and older Jewish and Egyptian ideas. Origen answers by appeal to Jewish scripture read as prophecy, to Greek philosophy itself (particularly Plato and the Stoics, whom he uses both as allies and as targets), and to arguments about the moral transformation Christian teaching produces in ordinary people.
The work matters because it is a rare direct textual encounter between a sophisticated pagan critic and a sophisticated Christian defender, both writing in Greek, roughly a century apart, with the accusations preserved verbatim inside the rebuttal. It shows what an educated Greco-Roman reader in the 170s CE actually knew and objected to about Christian claims, and it shows how a leading Christian intellectual of the mid-third century mounted a systematic defense that anticipates apologetic strategies used for the next 1,700 years, from proof-from-prophecy to arguments about the plainness of style as a strength rather than a weakness.
“Our Savior and Lord Jesus Christ, when falsely accused, "kept silent," and when charged, "made no answer," persuaded that his whole life and his deeds among the Jews were stronger than any voice that”
— Against Celsus, Book 1 · read this chapter →
“Now the chief priest and the council sought false testimony against Jesus, so that they might put him to death, and found none, though many false witnesses came forward.”
— Against Celsus, Book 1 · read this chapter →
“I have already reached the completion of seven books, and I wish to begin an eighth as well.”
— Against Celsus, Book 8 · read this chapter →
“One can see, at any rate, that Plato is in the hands only of those who are thought to be lovers of literature, while Epictetus is admired even by ordinary”
— Against Celsus, Book 6 · read this chapter →
“But in fact these gods take strong vengeance on the one who blasphemes, either making him flee and hide because of it, or having him caught and destroyed.”
— Against Celsus, Book 8 · read this chapter →
It is Origen's book-by-book rebuttal of a lost pagan treatise, The True Word, by the philosopher Celsus, who had attacked Christianity as intellectually crude, magically fraudulent, and dependent on a scandalous rumor about Jesus's birth. Origen answers each charge in turn, quoting Celsus extensively along the way, which makes the work our best surviving window onto second-century pagan objections to Christianity.
Celsus was a Greek philosopher, likely writing around 175-180 CE, whose anti-Christian treatise survives only through Origen's quotations of it in this work. Origen treats him as a serious opponent worth answering point by point rather than dismissing.
At the opening of Book 1, Origen argues that Jesus deliberately kept silent when falsely accused and gave no answer when charged, trusting that his life and deeds among the Jews spoke louder than any defense speech could.
In Book 6 he argues that plainness is a strength, not a defect: Plato's philosophy reaches only the literary elite, while a simpler teacher like Epictetus is admired even by ordinary people, and Christian preaching aims deliberately at that wider, more practical reach.
Yes. Because Origen quotes Celsus at length before responding, the treatise preserves substantial verbatim material from a lost pagan critique, making it one of the few direct records of educated Greco-Roman objections to Christian claims from the 170s CE.
It runs to eight books, written by Origen in response to repeated urging from his patron Ambrose, and it stands as one of the longest and most systematic works of early Christian apologetics.