The break between the Catholic Church and Protestant Reformers was primarily caused by disputes over church practices, theology, and authority. Key figures like Martin Luther criticized the Catholic Church's sale of indulgences and emphasized justification by faith alone. The 1517 posting of Luther's Ninety-Five Theses sparked broader calls for reform, leading to significant theological disagreements on salvation, the authority of Scripture, and the nature of the Church. This schism resulted in the establishment of various Protestant denominations, reshaping Christianity and religious practices in Europe, and contributing to significant social, political, and cultural changes that would last for centuries.