"Of all the ancient sources for Jesus, the least favorably biased seem to be rabbinic in origin. There are actually a significant number of references to Jesus in the Jewish tradition, but many of them use names like "that man" when they refer to Jesus Christ. Therefore, some of the references are now considered unreliable.
Regardless, in the Babylonian Talmud, the formal commentary on the Jewish Laws compiled between 200-500 AD, there's a powerful reference to Jesus:
It has been taught: On the Eve of the Passover, they hanged Yeshu. And an announcer went out in front of him, for forty days saying: 'he is going to be stoned because he practiced sorcery and enticed and led Israel astray.' Anyone who knows anything in his favor, let him come and plead in his behalf.' But, not having found anything in his favor, they hanged him on the Eve of the Passover.
This is considered to be a very credible reference to Jesus ("Yeshu") from the Jewish tradition. Here, the rabbinical writers verify that Jesus was an historic figure, that he was crucified on the eve of the Passover and that he did miracles, referred to as "sorcery." The events surrounding the life of Jesus were not denied, but definitely verified in the Jewish tradition.
Well, I was looking for unbiased sources, outside the Bible, that speak to the person of Jesus, his death by capital punishment, and the rise of a religion in his name. Remarkably, that's exactly what I got!
The non-Christian historical accounts of Cornelius Tacitus, Flavius Josephus, Pliny the Younger, Suetonius, Mara Bar-Serapion, Lucan of Samosata, and even the writings of the extremely biased Jewish Sanhedrin all vindicate the Biblical accounts of the life and death of Jesus Christ in the first century AD.
In addition to the nine New Testament authors who wrote about Jesus in separate accounts, I found at least twenty additional early Christian authors, four heretical writings, and seven non-Christian sources that make explicit mention of Jesus in their writings within 150 years of his life. This amounts to a minimum of 40 authors, all of whom explicitly mention Jesus and the expansion of a spiritual movement in his name. More authors mention Jesus Christ within 150 years of his life than mention the Roman Emperor who reigned during His lifetime. Scholars are only aware of ten sources that mention Emperor Tiberius within 150 years of his life, including Luke, Tacitus, Suetonius, and Paterculus. Thus, within this short time frame, the number of ancient writers who mention Jesus outnumber those who mention the leader of the entire Roman Empire (effectively, the ancient world of the time) by a ratio of 4:1!"