Social Media And The Protestant Reformation

Also via Ritholtz, The Economist examines how Luther's ideas spread in the 16th Century:

The start of the Reformation is usually dated to Luther’s nailing of his “95 Theses on the Power and Efficacy of Indulgences” to the church door in Wittenberg on October 31st 1517. The “95 Theses” were propositions written in Latin that he wished to discuss, in the academic custom of the day, in an open debate at the university. Luther, then an obscure theologian and minister, was outraged by the behaviour of Johann Tetzel, a Dominican friar who was selling indulgences to raise money to fund the pet project of his boss, Pope Leo X: the reconstruction of St Peter’s Basilica in Rome. Hand over your money, went Tetzel’s sales pitch, and you can ensure that your dead relatives are not stuck in purgatory. This crude commercialisation of the doctrine of indulgences, encapsulated in Tetzel’s slogan—“As soon as the coin in the coffer rings, so the soul from purgatory springs”—was, to Luther, “the pious defrauding of the faithful” and a glaring symptom of the need for broad reform. Pinning a list of propositions to the church door, which doubled as the university notice board, was a standard way to announce a public debate.
Although they were written in Latin, the “95 Theses” caused an immediate stir, first within academic circles in Wittenberg and then farther afield. In December 1517 printed editions of the theses, in the form of pamphlets and broadsheets, appeared simultaneously in Leipzig, Nuremberg and Basel, paid for by Luther’s friends to whom he had sent copies. German translations, which could be read by a wider public than Latin-speaking academics and clergy, soon followed and quickly spread throughout the German-speaking lands. Luther’s friend Friedrich Myconius later wrote that “hardly 14 days had passed when these propositions were known throughout Germany and within four weeks almost all of Christendom was familiar with them.”
The unintentional but rapid spread of the “95 Theses” alerted Luther to the way in which media passed from one person to another could quickly reach a wide audience. “They are printed and circulated far beyond my expectation,” he wrote in March 1518 to a publisher in Nuremberg who had published a German translation of the theses. But writing in scholarly Latin and then translating it into German was not the best way to address the wider public. Luther wrote that he “should have spoken far differently and more distinctly had I known what was going to happen.” For the publication later that month of his “Sermon on Indulgences and Grace”, he switched to German, avoiding regional vocabulary to ensure that his words were intelligible from the Rhineland to Saxony. The pamphlet, an instant hit, is regarded by many as the true starting point of the Reformation.