The series of events referred to as the Protestant Reformation began in the early 16th century as a movement against the practices and doctrines of the Roman Catholic Church. Key figures such as Martin Luther and John Calvin criticized corruption, particularly the sale of indulgences and sought to reform church practices. The Reformation led to the establishment of Protestant denominations, significant changes in religious belief, and social and political upheavel across Europe, fostering greater emphasis on individual interpretation of the Bible.