Justin Martyr (c. 100-165 CE) was a second century Christian of pagan origins. A number of splendid works (including several clear forgeries) are attributed to him, notably a defence of Christianity supposedly addressed to the emperor of Rome [cj].
Of the major apologists up until c. 180 CE, Justin is the only one to have supposedly mentioned Jesus Christ as a historical figure [2a].
However, it is impossible to be sure that Justin actually wrote anything attributed to him [cj] [rb].
Doctrinal Differences
The works attributed to Justin do not mention the works of Paul directly, and never "name" any of the four Gospels. They talk of the husband of Jesus's mother being part of the burial of Jesus; a fire being kindled in the river Jordan at the baptism of Christ and Jesus's works as a carpenter [rb].
As with Clement of Alexandria, Augustine, and other ancient Christian authorities, "Justin" claims that Jesus was first recognised as the Son of God at the time of his baptism - and not at his birth as the now-recognised "Gospels" claim. [rt].
The reliability of Justin Martyr himself is called into question by his assertion in Chapter 25 of his First Apology that the Romans had a record of the crucifixion of Jesus [fj].
These works are however valuable evidence of the changes in Christian teachings in the first few centuries of its existence.
Pagan Appeal
Justin's apologies pointedly refer to the existence of Jesus Christ, the crucifixion and physical resurrection. In fact, he made a point of stressing how similar Christian teaching was to the ancient Greeks of five hundred years before [fj]:
"...though we say things similar to what the Greeks say, we only are hated on account of the name of Christ..."
Quite marvelously, they claimed that the Greek received their wisdom (somehow) from Moses:
"And that you may learn that it was from our teachers - we mean the account given through the prophets - that Plato borrowed his statement that God..."
Even more spectacular is the claim that the similarities between Christianity and pagan mythology were due to the devil anticipating the birth of Christ, and planting these stories to confuse and confound mankind when Jesus finally did arrive [fj]:
"...For having heard it proclaimed through the prophets that the Christ was to come, and that the ungodly among men were to be punished by fire, they put forward many to be called sons of Jupiter, under the impression that they would be able to produce in men the idea that the things which were said with regard to Christ were mere marvellous tales... And these things were said both among the Greeks and among all nations where they [the demons] heard the prophets foretelling that Christ would specially be believed in..."
Conclusion
In short, by recognising the similarities between Christian myths and pagan ones, the Apology of Justin provides clear reason to doubt the existence of Jesus Christ as anything other than a legendary hero, in the vein of any number of other mythical god-men.
(This document is a work in progress. Please contact me with any further information.)
Is the Bible Devine? Roberts-Bradlaugh Debate, 1876. (In his first speech on day four of this infamous debate, the atheist Mr. Bradlaugh claimed that all of the works attributed to Justin were fakes. The Christian Mr Robert's third reply derided Justin's works as "trashy"). Justin's claims regarding the "fire kindled in the river Jordan" and the carptentry of Jesus are contained in Ap 2.48. [rb]