Which event sparked the Protestant Reformation?

The posting of Martin Luther’s Ninety-Five Theses in 1517 is widely regarded as the catalyst for the Protestant Reformation. Luther's document criticized the Catholic Church's practices, particularly the sale of indulgences, which he viewed as corrupt and contrary to the teachings of the Bible. By publicly challenging the church's authority and practices, Luther ignited a movement that questioned the foundations of Catholicism and led to the establishment of various Protestant denominations.

This event is significant because it not only sparked theological debates but also empowered others to speak out against church abuses, leading to a broader religious transformation across Europe. Luther’s actions inspired other reformers, fostered new interpretations of Christian doctrine, and ultimately contributed to significant social, political, and cultural changes. The other options reflect important developments in the Reformation era but did not initiate the movement itself.