Early Christianity was generally considered to be a sect of Judaism. Paul appears to have considered himself a Jew. We also know that Christians were still welcome in the Temple until its destruction in the year 70, and that they attended Jewish synagogues. On the other hand, John's Gospel, written early in the second century, shows that Christians were beginning to see themselves as distinct from Jews. John was openly hostile to the Jews and referred to "Jews" generically, in contexts where the earlier Gospels directed their criticism towards the Pharisees alone.
The break came in 85 CE, when Christians were banned from the synagogues. From this time, Jews attending the synagogues were required to condemn the Christians, to ensure that Christians did not quietly attend Jewish services without disclosing their true religious beliefs.
The way the question is phrased is backwards. It was Jews who believed that Jesus Christ was the Messiah who broke off from Judaism and founded Christianity, making Christianity the separate faith. This breaking-off occurred in the 1st and 2nd centuries. It occurred as early Christians began to form their own synagogues, to accept as members non-Jewish men who did not become circumcised, and began to preach values that were distinct from the larger Jewish community.
After the death and resurrection of Jesus Christ.
Judaism and Islam separate men from women in ritual worship but not in the workplace.
Judaism, Christianity, and Islam religions.
The three major monotheistic religions are Judaism, Christianity, and Islam. These religions believe in one God and have sacred texts such as the Torah, the Bible, and the Quran.
Islam and Judaism are two distinct monotheistic religions that share part of their history.
-- Islam -- Judaism -- Christianity
Three religions with holy sites in the eastern Mediterranean are Christianity (including sites like Jerusalem and Bethlehem), Judaism (with sites such as the Western Wall in Jerusalem), and Islam (with sites like the Dome of the Rock and Al-Aqsa Mosque in Jerusalem).
Islam, Christianity & Judaism
Judaism & Islam
Islam Buddhism Judaism
Christianity and Islam ^^
Mandaeism, Christianity and Islam are three religions that derive rather directly from Judaism.
Islam and Christianity, or Islam and Judaism