If Jesus was a Jew, how could he have been the Messiah to Chrisitians , if Jews were and still are waiting for the Messiah to come?
Siddhartha was a Hindu and created Buddhism
Jesus Christ was not recognized as a Messiah by the Judaist community, and this caused divergence of the two religions that have the same root: Christianity and Judaism. People of different ethnic origin (including Jews, e.g. St. Peter, St. Paul, etc. that were ethnic Jews) that recognized the Messianic nature of the Savior were the first Christians.
Was Jesus a Messianic Jew?
No, he was the Messiah Himself. But his personal background, both ethnic and cultural, was Jewish. Well, I am discussing His human impersonation, since, in fact, Jesus Christ is not exactly a human being , He is God the Son, a part of the Trinity. As God the Son, He surely does not have any ethnic affiliation.