Martin Luther, an Augustinian monk in 16th-century Germany, sparked a religious and cultural revolution known as the Reformation. His posting of the Ninety-Five Theses in 1517 challenged the abuses of the Catholic Church, leading to his excommunication and the birth of Protestantism. The Reformation significantly impacted the political landscape of Europe, as it influenced the rise of nation-states and the decline of the Holy Roman Empire. The religious divide within the empire contributed to conflicts like the Schmalkaldic War and ultimately led to the Peace of Augsburg in 1555, which established the principle of "cuius regio, eius religio" ("whose realm, his religion"), granting rulers the right to determine the religion of their subjects.
