Judaism
There are some movements that combine elements of Judaism with those of other religions. The most well-known of these is Messianic Judaism, a religious movement, which arose in the 1960s, that incorporates elements of Judaism with the tenets of Christianity. The movement generally states that Jesus is the Jewish Messiah, that he is one of the Three Divine Persons, and that salvation is only achieved through acceptance of Jesus as one's savior. Some members of the movement argue that Messianic Judaism is a sect of Judaism. Jewish organizations of every denomination reject this, stating that Messianic Judaism is a Christian sect, because it teaches creeds which are identical to those of Pauline Christianity.
Origins of Christianity
Several Jewish sects are known to have existed during the 1st century CE: the Essenes, Pharisees, Sadducees, Zealots, and Christians. After the destruction of the Second Temple in 70 CE, most of these sects vanished, but Christianity and the Pharisees survived, with Christianity gradually becoming a separate religion, and the Pharisees developing into Rabbinic Judaism, or simply Judaism. Rather than a sudden split, there was a slowly growing chasm between Christians and Jews in the 1st centuries, and it took centuries for a complete break to manifest.