Celsus

Celsus was a 2nd-century Greek philosopher and opponent of early Christianity. His literary work, The True Word, survives exclusively in quotations from it in Contra Celsum, a refutation written in 248 by Origen of Alexandria. The True Word is the earliest known comprehensive criticism of Christianity. Hanegraaff has argued that it was written shortly after the death of Justin Martyr, and was probably a response to his work. Origen stated that Celsus was from the first half of the 2nd century AD, although the majority of modern scholars have come to a general consensus that Celsus probably wrote around AD 170 to 180.