Christianity is one of the best examples in history of a little religion that made it big in the world. At the death of Jesus (and the conversion of Paul), there were twelve apostles, the original disciples of Jesus who were imbued with the Holy Spirit to teach Christianity to the masses. At the beginning, each had equal status, and the major doctrine (developed by Paul) was salvation for those who believed in the saving grace of Jesus and who underwent Baptism., the ritual which cleansed the soul. Paul added the theological point that Christians were the "true Israel," the Israel of faith rather than the crude Israel of the flesh (the Jews).
The Christians felt that because they were preaching to non-Jews, they had to discredit the status of Jews by emphasizing their lack of faith and their fall from favor because they didn't accept the teachings of the Messiah, of Christ.
As in all new religions, Christianity had birth-pangs. The major assumption of the budding religion was that the Messiah had come and that the New Age was at hand. This idea could not last for very long before it started losing its immediacy. If the New Age was at hand, why wasn't anything new happening? Paul's answer was that something new was happening. The Christians just had to look inside themselves to see how much change there was.
This response couldn't last very long either; it encouraged people to provide personal answers to theological questions. There had to be official, concrete answers and rules to the questions emerging through the community. First, the leadership agreed that the only ones who could teach and describe the truths of the new religion were students of the apostles. Each apostle specified a special student to take over the teaching and explaining when he died. This student in turn taught other students, specifying one as the special student to continue the teaching. This line of students from the original twelve apostles through the generations was called the Apostolic Line. It successfully challenged the legitimacy of any other group as being the New Israel.
However, this legitimate New Israel now had to define itself; what did it really believe? What was the truth? The leading Christian thinkers from 80 CE until 420 CE spent most of their time writing defenses and arguments against heretical arguments; applying proof texts from Scripture to their theology, and concretizing the beliefs of the new religion. These writings were called Apologies, and the early Church fathers were called Apologists.
In their zeal to justify early Church doctrine, the Apologists inevitably vilified the Jews. In making Christianity the New Israel, they had to explain the sins of the Old Israel, the fallen Israel, the false Israel.
The first apologist to do this was a newly-converted Christian named Justin Martyr (who was later killed by the Romans). In 145 CE (ten years after the Bar Kochba Revolt) Justin Martyr wrote an apology in which he was having a dialogue with a Jew named Trypho. Using Bible proof texts, Justin Martyr claimed that the Jews were originally selected by God because they were such an unspiritual group; they needed added laws. He blasted the Jews for rejecting Jesus, for killing Jesus, for leading people away from salvation. He gloated over the destruction of the Temple as being just punishment for Jewish perfidy. Justin Martyr's writings became incorporated into early Christian thought, and were the origins of Christian anti-Semitism.