Why is there no pagan historical evidence written by authors who were alive during the life of Jesus?

*"What kinds of things did the pagan authors of Jesus time have to say about him?"* asks Dr. Bart Ehrman in his book Jesus: *Apocalyptic Prophet of the New Millenum (Oxford University Press)*. *"Nothing,"* he answers. *"Strange as it may seem, there is no mention of Jesus by any of his pagan contemporaries."*, Ehrman asserts in his book. *"There are no birth records, no transcripts of his trial, no death certificates; no expressions of interest, no slander, no passing references. Nothing. In fact, if we extend our field of study to the years after his death - including the entire first century of our era - there is not a single reference to Jesus in any source either Christian or Jewish of any kind. I should point out that we have a large number of documents from the period: writings of poets, philosophers, historians, scientists, government officials... Not to mention the large collection of stone inscriptions, private letters and legal documents on papyrus. In none of these documents does the name of Jesus even appear".* Why is the first pagan historical evidence that Jesus existed years after his crucifixion (Flavius Josephus)?