Paul the Apostle and anti-semitism

Yesterday one of my friends (an ethnic Jew) declared that if he could go back in time and erase any one person's existence, it would be Paul the Apostle. He reasoned that Paul is the first source of anti-semitism in Christianity, and that without his writings and his influence with regard to the spread of Christianity, the religion may have never gotten its feet off the ground and many years of bigotry and violent acts would have been erased without any precedent.

I'd like to hear your thoughts. Would Christianity be a major religion today without Paul? Would its followers (Catholics in the Middle Ages specifically) have displayed such anti-semitic behavior without Paul?