It is important to recognize that in A.D. 70, the Romans invaded and destroyed Jerusalem and most of Israel, slaughtering its inhabitants. Entire cities were literally burned to the ground. We should not be surprised, then, if much evidence of Jesus' existence was destroyed. Many of the eyewitnesses of Jesus would have been killed. These facts likely limited the amount of surviving eyewitness testimony of Jesus.
Considering that Jesus' ministry was largely confined to a relatively unimportant area in a small corner of the Roman Empire, a surprising amount of information about Jesus can be drawn from secular historical sources. Some of the more important historical evidences of Jesus include the following:
The first-century Roman Tacitus, who is considered one of the more accurate historians of the ancient world, mentioned superstitious “Christians” (from Christus, which is Latin for Christ), who suffered under Pontius Pilate during the reign of Tiberius. Suetonius, chief secretary to Emperor Hadrian, wrote that there was a man named Chrestus (or Christ) who lived during the first century (Annals 15.44).
Flavius Josephus is the most famous Jewish historian. In his Antiquities he refers to James, “the brother of Jesus, who was called Christ.” There is a controversial verse (18:3) that says, “Now there was about this time Jesus, a wise man, if it be lawful to call him a man. For he was one who wrought surprising feats....He was [the] Christ...he appeared to them alive again the third day, as the divine prophets had foretold these and ten thousand other wonderful things concerning him.” One version reads, “At this time there was a wise man named Jesus. His conduct was good and [he] was known to be virtuous. And many people from among the Jews and the other nations became his disciples. Pilate condemned him to be crucified and to die. But those who became his disciples did not abandon his discipleship. They reported that he had appeared to them three days after his crucifixion, and that he was alive; accordingly he was perhaps the Messiah, concerning whom the prophets have recounted wonders.”
Julius Africanus quotes the historian Thallus in a discussion of the darkness which followed the crucifixion of Christ (Extant Writings, 18).
Pliny the Younger, in Letters 10:96, recorded early Christian worship practices including the fact that Christians worshiped Jesus as God and were very ethical, and he includes a reference to the love feast and Lord’s Supper.
The Babylonian Talmud (Sanhedrin 43a) confirms Jesus' crucifixion on the eve of Passover and the accusations against Christ of practicing sorcery and encouraging Jewish apostasy.
Lucian of Samosata was a second-century Greek writer who admits that Jesus was worshiped by Christians, introduced new teachings, and was crucified for them. He said that Jesus' teachings included the brotherhood of believers, the importance of conversion, and the importance of denying other gods. Christians lived according to Jesus’ laws, believed themselves to be immortal, and were characterized by contempt for death, voluntary self-devotion, and renunciation of material goods.
Mara Bar-Serapion confirms that Jesus was thought to be a wise and virtuous man, was considered by many to be the king of Israel, was put to death by the Jews, and lived on in the teachings of His followers.
Then we have all the Gnostic writings (The Gospel of Truth, The Apocryphon of John, The Gospel of Thomas, The Treatise on Resurrection, etc.) that all mention Jesus.
In fact, we can almost reconstruct the gospel just from early non-Christian sources: Jesus was called the Christ (Josephus), did “magic,” led Israel into new teachings, and was hanged on Passover for them (Babylonian Talmud) in Judea (Tacitus), but claimed to be God and would return (Eliezar), which his followers believed, worshipping Him as God (Pliny the Younger).
There is overwhelming evidence for the existence of Jesus Christ, both in secular and biblical history. Perhaps the greatest evidence that Jesus did exist is the fact that literally thousands of Christians in the first century A.D., including the twelve apostles, were willing to give their lives as martyrs for Jesus Christ. People will die for what they believe to be true, but no one will die for what they know to be a lie.