The letter from the Syrian Mara Bar-Serapion to his son (after 73 ad) mentions Jesus as a historical figure: 

“What advantage did the Athenians gain from putting Socrates to death?  Famine and plague came upon them as a judgment for their crime.  What advantage did the men of Samos gain from burning Pythagoras?  In a moment their land was covered with sand.  What advantage did the Jews gain from executing their wise King?  It was just after that that their kingdom was abolished.  God justly avenged these three wise men: the Athenians died of hunger, the Samians were overwhelmed by the sea; the Jews, ruined and driven from their land, live in complete dispersion.  But Socrates did not die for good, he lived on in the teaching of Plato.  Pythagoras did not die for good; he lived on in the statue of Hera.  Nor did the wise King die for good; he lived on in the teaching which He had given.”

The Jewish historian Josephus (93 ad) wrote about Jesus, and Josephus clearly speaks of Jesus as a historical person - Josephus also confirms the historicity of many New Testament events.

“Now, there was about this time Jesus, a wise man, if it be lawful to call him a man, for he was a doer of wonderful works - a teacher of such men as receive the truth with pleasure.  He drew over to him both many of the Jews, and many of the Gentiles.  He was [the] Christ; and when Pilate, at the suggestion of the principal men amongst us, had condemned him to the cross, those that loved him at the first did not forsake him, for he appeared to them alive again the third day, as the divine prophets had foretold these and ten thousand other wonderful things concerning him; and the tribe of Christians, so name from him, are not extinct at this day.” (Josephus, Antiquities of the Jews, Book 18, chapter 3, paragraph 3)

Lucian was a Roman comedian who wrote about Christians in the second century: 

[Jesus was] “ . . . the man who was crucified in Palestine because he introduced this new cult into the world . . . Furthermore, their first lawgiver persuaded them that they were all brothers of one another after they have transgressed once for all by denying the Greek gods and by worshipping that crucified sophist himself and living under his laws.” (Lucian, The Passing Peregruis)

The Jewish rabbinical writings after the destruction of Jerusalem (the Mishna) several times mention Jesus as a historical figure (135-300 ad).  This is from the Talmud:

“On the eve of Passover Yeshua as hanged.  For forty days before the execution took place, a herald went forth and cried, ‘he is going forth to be stoned because he has practiced sorcery and enticed Israel to apostasy.  Anyone who can say anything in his favour, let him come forward and plead on his behalf.’  But since nothing was brought forward in his favour he was hanged on the eve of the Passover.” (The Babylonian Talmud, Sanhedrin, 43a).

When Justin Martyr writes to a Jew name Trypho in 147 ad, he can confidently say:

“You Jews knew that Jesus was risen from the dead, and ascended into heaven, as the prophecies did foretell was to happen.” (Dialogue with Trypho)

About 150 ad, Justin Martyr makes reference to documents which he believed to be in the archives at Rome - Pilate’s report back to the emperor about what happened with this “Jesus.”

“‘They pierced my hands and my feet’ are a description of the nails that were fixed in His hands and His feet on the cross; and after He was crucified, those who crucified Him cast lots for His garments, and divided them among themselves; and that these things were so, you may learn from the ‘Acts’ which were recorded under Pontius Pilate . . . That He performed these miracles you may easily be satisfied from the ‘Acts’ of Pontius Pilate.” (Justin Martyr, Apology, 1.48)

The Roman historian Cornelius Tacitus (115 ad) wrote about Nero’s persecution of Christians in the time of Nero (54-68 ad):

“Consequently, to get rid of the report, Nero fastened the guilt and inflicted the most exquisite tortures on a class hated for their abominations, called Christians by the populace.  Christus, from whom the name had its origin, suffered the extreme penalty during the reign of Tiberius at the hands of one of our procurators, Pontius Pilate, and a most mischievous superstition, thus checked for the moment, again broke out not only in Judea, the first source of the evil, but even in Rome, where all things hideous and shameful from every part of the world find their center and become popular. Accordingly, an arrest was first made of all who pleaded guilty; then, upon their information, and in Rome an immense multitude was convicted, not so much on the charge of arson as because of their hatred of the human race.  Besides being put to death they were made to serve as objects of amusement; they were clad in the hides of beasts and torn to pieces by dogs; others were crucified, others set on fire to serve to illuminate the night when daylight failed.” (Tacitus, 15:44)

Tacitus himself saw that Christians were “Being destroyed, not for the public good, but to gratify the cruelty of an individual.”