Evidence from Lucian
Lucian of Samosata was a second century Greek satirist. In one of his works, he wrote of the early Christians as follows:
The Christians . . . worship a man to this day--the distinguished personage who introduced their novel rites, and was crucified on that account. . . . [It] was impressed on them by their original lawgiver that they are all brothers, from the moment that they are converted, and deny the gods of Greece, and worship the crucified sage, and live after his laws.{27}
Although Lucian is jesting here at the early Christians, he does make some significant comments about their founder. For instance, he says the Christians worshipped a man, "who introduced their novel rites." And though this man's followers clearly thought quite highly of Him, He so angered many of His contemporaries with His teaching that He "was crucified on that account."
Although Lucian does not mention his name, he is clearly referring to Jesus. But what did Jesus teach to arouse such wrath? According to Lucian, he taught that all men are brothers from the moment of their conversion. That's harmless enough. But what did this conversion involve? It involved denying the Greek gods, worshipping Jesus, and living according to His teachings. It's not too difficult to imagine someone being killed for teaching that. Though Lucian doesn't say so explicitly, the Christian denial of other gods combined with their worship of Jesus implies the belief that Jesus was more than human. Since they denied other gods in order to worship Him, they apparently thought Jesus a greater God than any that Greece had to offer!
Let's summarize what we've learned about Jesus from this examination of ancient non-Christian sources. First, both Josephus and Lucian indicate that Jesus was regarded as wise. Second, Pliny, the Talmud, and Lucian imply He was a powerful and revered teacher. Third, both Josephus and the Talmud indicate He performed miraculous feats. Fourth, Tacitus, Josephus, the Talmud, and Lucian all mention that He was crucified. Tacitus and Josephus say this occurred under Pontius Pilate. And the Talmud declares it happened on the eve of Passover. Fifth, there are possible references to the Christian belief in Jesus' resurrection in both Tacitus and Josephus. Sixth, Josephus records that Jesus' followers believed He was the Christ, or Messiah. And finally, both Pliny and Lucian indicate that Christians worshipped Jesus as God!
I hope you see how this small selection of ancient non-Christian sources helps corroborate our knowledge of Jesus from the gospels. Of course, there are many ancient Christian sources of information about Jesus as well. But since the historical reliability of the canonical gospels is so well established, I invite you to read those for an authoritative "life of Jesus!"