What significant event is considered the start of the Protestant Reformation?

Martin Luther's posting of the Ninety-Five Theses is widely recognized as the catalyst for the Protestant Reformation. This pivotal act occurred in 1517 when Luther publicly challenged the practices of the Catholic Church, particularly the sale of indulgences, which he viewed as corrupt and contrary to biblical teachings. By nailing his theses to the church door in Wittenberg, Luther not only sparked a theological debate but also galvanized a movement that questioned the authority of the Pope and the practices of the Church. This event marked the beginning of a widespread reevaluation of religious beliefs and led to the formation of various Protestant denominations, fundamentally altering the religious landscape of Europe.

The other events listed, while significant in their own right, occurred later in the timeline of the Reformation or represented outcomes rather than the initial spark of the movement itself. The Council of Trent, for example, was convened in 1545 as a response to the Reformation, aiming to address issues within the Catholic Church. The Edict of Nantes was issued in 1598 to grant religious freedom to the Huguenots in France, representing a later development in the ongoing conflicts between Catholics and Protestants. Meanwhile, Henry VIII's declaration of the Church of England took place in