A German monk and professor, incensed by the Church's sale of indulgences, posts a list of ninety-five arguments for scholarly debate on a church door in Wittenberg. Copies spread rapidly via the new printing press, turning a local theological dispute into a continent-wide upheaval that splits Western Christianity and reshapes European politics for centuries.
Martin Luther was, by his own account, less interested in revolution than in academic debate. The Ninety-Five Theses were written in Latin, aimed at fellow clergy and scholars, questioning the Church's practice of selling indulgences that promised to reduce time in purgatory for a price. Whether he actually hammered them to the door himself or simply mailed them to the local bishop remains disputed by historians, but the legend of the nail and the door stuck.
What made the difference was Gutenberg's press, invented some sixty years earlier. Within weeks, translated and reprinted copies of Luther's arguments were circulating across German-speaking lands, then beyond. The Church that had survived a thousand years of heresies now faced a movement it could not simply excommunicate into silence.
The consequences unspooled over decades: religious wars, the founding of Protestant denominations, and a permanent fracture in European Christendom. Luther himself, hauled before the Diet of Worms four years later, refused to recant unless proven wrong by scripture — a stance that made him an outlaw of the Empire and a hero to millions.