[T]he Roman historian, Tacitus (who was born in a.d 55), wrote in his Annals (15:44) an explanation of how Nero, the emperor (who died in a.d 68) blamed Christians for the great fire of Rome in order to deflect rumors that he had started the blaze. In this passage Tacitus alludes to a fact which no one disputed: Christ had been crucified under Pontius Pilate:
All human efforts . . . of the emperor, and the propitiations of the gods, did not banish the sinister belief that the conflagration was the result of an order. 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 Pilatus , 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.
It was common and undisputed knowledge in the second half of the first century that Jesus Christ had been crucified. If there were any question that he had died in this way, it would have been eagerly disputed wherever Christians preached. But it wasn't. The fact of his death by crucifixion was not questioned.
Taken from "The Great Offense: Was Jesus Really Crucified?" by John Piper. © Desiring God. Website: desiringGod.org (used by permission).