This is disingenuous when you dig into it. There is little information about the existence of Jesus in Roman records, but it more or less just states he was executed during the reign of Tiberius. It appears that the described followers of Christus were regarded as a kind of minor nuisance and cult originally.
Tactius wrote:
"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 Judæa, the first source of the evil, but even in Rome, where all things hideous and shameful from every part of the world find their centre and become popular."
Now, I will say that the Romans knew time was long, and were notorious for editing history for purposes of future historical perspective. Their Depictions of the celts in both words and art are more or less pure propaganda. The celts were reasonably developed as a civilization. Certainly they were not the mindless savages Roman art would have people believe they were.