When the early church underwent a schism does that mean it changed its most important doctrines?

When the early church underwent schisms, such as the Great Schism of 1054 or the Protestant Reformation, it often involved disagreements over practices, authority, and interpretations of doctrine rather than a fundamental change in core beliefs. While some groups may have emphasized different aspects of doctrine or developed new theological perspectives, key foundational beliefs, such as the divinity of Christ and the significance of the sacraments, generally remained intact. Schisms typically highlighted existing tensions rather than resulting in a complete overhaul of essential doctrines.