Christianity began as a sect of Judaism.
As the number of gentile members increased - which is what happened as the church took the Messiah’s gospel to the nations of the world -> the great commission implemented - the Jewish theology was gradually replaced.
That is how Christianity separated from Judaism.
The earliest Christians were Jews who believed Jesus is the Messiah. Christianity was a unique unit within Judaism.
Christianity is within Judaism …. (shift) …Christianity is without Judaism.
Sects within Christianity have historically been persecuted by Christianity. The sect founded by Jesus within Judaism was persecuted by Judaism.
The majority of Jews didn’t (and don’t) believe Jesus of Nazareth, himself a Jew, is the Messiah promised by the God of Judaism. A minority of Jews did (and still do.)
Let’s do it.
Trinitarian (Anglican) support for what I’ve described in post #98 @Riven.
”In later times the church no longer perceiving the power and decisiveness of the agent-son-representative model, and having among its members men used to a more philosophical analysis, felt it necessary to go further in the direction of metaphysical identity between Jesus and his heavenly Father : released from Jewish monotheism, gentile Christians began to think of Jesus as also, in some sense God.”
(A.E. Harvey, Jesus and the Constraints of History, p. 173)
I’ve placed in bold the shift in theology which happened in early church history. This is the breaking away, theologically, of Christianity from Judaism. Church leadership no longer Jewish.