Actually, the Romans had no idea who Jesus was. They nothinged him. It wasn't until his raid in the Temple that he even came to the attention of the Romans. It was at that point that Pilot decided to kill him. There's a good chance that the Sanhedrin and the Priestly class had heard of him... we know that the Pharisees had, but he was pretty much just a shaman until that event.

It was Paul, who turned Jesus into a Greek God that ended up having the last word. Jesus brother James, and Peter the disciple dogged Paul everywhere he went, telling Paul's followers that Paul was lying. However, when the Jewish wars began in 66, and Rome finally destroyed Jerusalem in 70, Jesus' disciples were wiped out. Paul was in Rome, along with Peter, but it was Paul's story that won the day.

Paul created the church in Rome which would eventually come to prominence in the late 200s, and finally be codified in the middle 300s. And as to Roman persecution of Christians, Romans didn't really care about Christians all that much. When it came to gods and other mythologies, they were quick to adopt the gods of the countries they conquered. It was an insurance policy for them. Take on all the gods so as not to piss any of them off. But Christians, very much like their counterparts the Jews, insisted on making a huge deal out of their sect. They invaded Roman festivals, threw over altars, and vandalized Roman statues, thus giving Rome a good reason to persecute them.

Religion is just a form of relating to our mythology, and the human species has been doing it since it became conscious. To call that a disease is the same as Christians calling homosexuality sin... these things are part of our evolution, and they're here for a reason. Religion is a blunt tool, and it has definitely brought much suffering upon the earth, but that's because religion incorporates not only our mythologies, but also our bigotries, our biases, and our tribalism... and then makes them "sacred."