The Protestant Reformers were a group of religious leaders in the 16th century who sought to reform the practices and beliefs of the Roman Catholic Church. Key figures included Martin Luther, who challenged the sale of indulgences, and John Calvin, who emphasized predestination and a more personal relationship with God. Their efforts led to the establishment of various Protestant denominations. The movement began in Germany and spread across Europe, resulting in significant changes in Christianity. The Reformers advocated for the translation of the Bible into vernacular languages, allowing more people to access religious texts. This shift contributed to the rise of individual interpretation of scripture and the decline of papal authority.