The Protestant Reformation began in 1517, marked by Martin Luther’s posting of his Ninety-Five Theses on the doors of the Castle Church in Wittenberg, Germany. This act challenged the practices and doctrines of the Roman Catholic Church, particularly the sale of indulgences, which Luther saw as corrupt. The Reformation sparked a religious revolution that questioned papal authority, led to the establishment of various Protestant denominations, and ultimately resulted in significant political and cultural changes across Europe. It also instigated conflicts and wars, shaping the course of Western history for centuries to come.