Who is often credited as one of the key figures in the Protestant Reformation?

Martin Luther is often credited as one of the key figures in the Protestant Reformation due to his instrumental role in challenging the practices and doctrines of the Catholic Church in the early 16th century. His posting of the Ninety-Five Theses in 1517 is widely recognized as the catalyst that sparked widespread debate about Church practices, particularly the selling of indulgences. Luther's emphasis on justification by faith alone, the authority of Scripture over Church traditions, and the priesthood of all believers laid the foundational principles of Protestantism.

His influence extended beyond just theological discussions; it also inspired a movement that led to the establishment of various Protestant denominations. Unlike Luther, John Calvin, while also a significant figure in the Reformation, came later and built upon Luther’s ideas rather than being the initial catalyst. Although Henry VIII played a critical role by initiating the English Reformation, his motivations were more politically driven than doctrinal. Thomas More, on the other hand, was a staunch opponent of the Reformation and remained loyal to the Catholic Church until his execution, therefore not contributing to Protestant reform.