The Reformation was a significant religious movement in the 16th century that aimed to reform the practices and beliefs of the Catholic Church. It led to the establishment of various Protestant denominations, including Lutheranism and Calvinism, as reformers like Martin Luther challenged the Church's authority and doctrines. This movement was sparked by issues such as the sale of indulgences and the desire for a more personal connection to faith. The Reformation not only transformed Christianity but also had profound effects on politics, culture, and society across Europe, paving the way for modern religious thought.