According to the Christian father Origen, Celsus (/ˈsɛlsəs/; Greek: ΚέΛΣΟς. K�lsos) was a 2nd-century Greek philosopher and opponent of Early Christianity. He is known for his literary work, The True Word (also Account, Doctrine or Discourse; Greek: ΛόΓΟς ἈΛΗ&thΗής), which survives exclusively in Origen's quotations from it in Contra Celsum. This work, c. 177 is the earliest known comprehensive attack on Christianity.According to Origen, Celsus was the author of an anti-Christian work titled The True Word (Alēthēs logos). This work was lost, but we have Origen's account of it in his writings. It was during the reign of Philip the Arab that Origen received this work for rebuttal. Origen's refutation of The True Word contained its text, interwoven with Origen's replies. Origen's work has survived and thereby preserved Celsus' work with it.Celsus seems to have been interested in Ancient Egyptian religion, and he seemed to know of Hellenistic Jewish logos-theology, both of which suggest The True Word was composed in Alexandria. Celsus wrote at a time when Christianity purportedly was being persecuted and when there seems to have been more than one emperor.As an anti-Christian Greek philosopher, Celsus mounted an attack on Christianity. Celsus wrote that some Jews said Jesus' father was a Roman soldier named Pantera. The views of Celsus drew responses from Origen who considered it a fabricated story. Raymond E. Brown states that the story of Pantera is a fanciful explanation of the birth of Jesus which includes very little historical evidence--Brown's analysis does not presuppose the doctrine of the "virgin birth", but cites the lack of historical evidence for Celsus' assertion. In addition, Celsus addressed the miracles of Jesus, holding that "Jesus performed His miracles by sorcery (ΓΟΗΤΕίΑ)".

Origen’s On First Principles is a foundational work in the development of Christian thought and doctrine: it is the first attempt in history at a systematic Christian theology. For over a decade it has been out of print with only expensive used copies available; now it is available at an affordable price and in a more accessible format. On First Principles is the most important surviving text written by third-century Church father, Origen. Origen wrote in a time when fundamental doctrines had not yet been fully articulated by the Church, and contributed to the very formation of Christianity. Readers see Origen grappling with the mysteries of salvation and brainstorming how they can be understood. This edition presents G. W. Butterworth’s trusted translation in a new, more readable format, retains the introduction by Henri de Lubac, and includes a new foreword by John C. Cavadini. As St. Gregory of Nazianzus, Doctor of the Church, wrote: “Origen is the stone on which all of us were sharpened.”

A critical edition of Origen's main and longest work "Contra Celsum."

The Case against Origen and Reincarnation surveys the writings of Origen, a controversial Christian theologian, whose life straddled the third and fourth centuries. By placing his work in the context of his theological predecessors, Eric Liberatos uses this analysis to trace the development of Origen's distinctive doctrines, such as reincarnation. His review of the history of the period concludes that Origen's condemnation by ecumenical councils arose from the virulent polemics and contentious politics of various ecclesiastical leaders of the period. The Case against Origen and Reincarnation will appeal to all who seek to understand the development of Christian thought and the influences of politics and personality on the church's theologies. Award-winning book that earned acclaim from the prestigious Next Generation Indie Book Awards! 2016 Winner in Religious Non-fiction 2016 Finalist in Historical Non fiction.

In a scholarly yet accessible manner, this book brings together classicists, experts in ancient Judaism and scholars in early Christianity, to discuss the neglected Greek philosopher Celsus, whose concerns touch upon a range of significant subjects in late antiquity.