Who actually established the Christian religion? Jesus Christ Himself, or Paul the Apostle?

It’s a question theologians have wrestled with mightily over the years. Some assert Jesus as a devote Jew never meant to replace Judaism as God’s official religion or Jews as God’s chosen people, and assert Paul’s teachings and writings are what actually led to the establishment of the Christian religion.

Never minding that your are or are not Christian, do you think Jesus the devote Jew meant to replace Judaism with a new Christian religion or to be the fulfillment of God’s promise to the Jews?