the reason judaism and christianity split is because in judaism they did not belive jesus was their Messiah and their messiah is yet to come. In christianity they accept jesus as the messiah due to the fact they are followers of christ. protestantism is a branched off of catholicism because of many reasons is because in their eyes the church had become bad and stopped conveying the true message of god and martin luther's 96-or 98 reasons why the church was bad