Who was Pontius Pilate (AKA, Pilate) that the Bible refers to so frequently in the Gospels?
Like many accounts in the Bible, there are not a lot of historical documents that exists today to better understand figures like this. But here's what can be assumed about him...
Pilate, being a Roman citizen, was likely a pagan; if you think pagan, and you think witchcraft, then you’re wrong. In Jesus' day, pagans were pretty much anyone who didn't believe in non-Abrahamic religion. The Romans inherited much of their belief system from the Greeks, which is to say that, by and large, it was Hellenistic--astrology was big for them, as was gods and goddesses. If you read the Gospel in more detail, you will notice that he seems intrigued by one particular aspect of Jesus' life: the miracles. Pagan's ate that stuff up.
Basically, Pilate's role in all of this was he was a Prefect of the providence Jesus was in. The Roman empire had around 40 or 50 such people. They were what we might consider a governor. What did a Prefect do? He had four key areas that he was responsible for:
1. Made sure the taxes were taken
2. He managed the money and supervised large scale building projects
3. Served as judge
4. Commanded army
Pilate, like all Prefects of his day, would have served a 2 to 4 year term.
Romans were pretty good about keeping records of stuff going on. After everything that took place, it can be assumed that Pilate would have sent out a letter explaining what went down. Here's where things get sketchy, however: no one knows were Pilate's letters went. There are several references in ancient text that refer to the "Acts of Pilate," but the only text that remains appears to be fabricated from the source material.
This is what "some" assume: the letters were sympathetic to the Christian cause, and may have actually given proof that they were right; pagans destroyed the letters to try and simmer down the Christian movement rapidly taking place. Christians recreated the letters with their own slant to replace them.
What's true? What's fake? Good question. Reading the Gospel, you get the impression that Christians were fans of his work. He was the one who sentenced Jesus to die, but you get the impression that he wasn't to blame--he was just doing his job (some even pushed the blame on Herold Antipas (more on that later)). This, as opposed to Jewish literature of the day, which made him out to be a stubborn troublemaker who killed people for the sport of it (you can read the Jewish attitudes towards Pilate in the works of two Jewish historians of the day: Philo of Alexandria and Josephus).
What became of Pilate? No one knows for sure, though many speculate he was exiled. What is known is Christians of the day were fascinated by him--perhaps there's a reason, and we just no longer have the text to tell us why.