Holy Roman Empire · 1517

What Did Martin Luther Do?

By William Souef · Published August 19, 2026

The indulgence machine and the 95 objections

By 1517, the theology of penance had grown a commercial appendage. An indulgence — remission of temporal punishment for sins already forgiven — could be granted for prayer or pilgrimage; increasingly, it could be bought. The campaign that reached Luther's region was explicitly transactional, half its proceeds flowing to Rome for the rebuilding of St Peter's and half to service the Archbishop of Mainz's debts. Tetzel's sales jingle, as Luther's side reported it: "As soon as the coin in the coffer rings, the soul from purgatory springs."

Luther — an Augustinian friar with a doctorate, lecturing on the Bible at the new university of Wittenberg — objected as a theologian, not yet a rebel. His 95 theses argued that repentance is an inner, lifelong turning; that the pope had no power over purgatory; and that selling false assurance endangered souls. He proposed a disputation, the normal academic procedure, and sent the theses to his archbishop — the man profiting from the sales.

The printing press turns a debate into a movement

What happened next had no precedent, because the technology enabling it was barely 60 years old. Printers in Leipzig, Nuremberg, and Basel had the theses out within weeks; German translations followed at once. Luther proved a pamphleteer of genius — short, cheap, vernacular tracts that sold in the hundreds of thousands — and the debate escalated with each exchange, from indulgences to the authority of the pope himself. Rome moved formally in 1520 with the bull Exsurge Domine, threatening excommunication; Luther burned it publicly. In January 1521 he was excommunicated.

Summoned that spring before Emperor Charles V at the Diet of Worms, and shown a table of his books, Luther refused to recant unless refuted from Scripture: his conscience, he said, was captive to the Word of God. The Edict of Worms declared him an outlaw. His prince, Frederick the Wise of Saxony, staged a masked "abduction" that hid him in Wartburg Castle — where, in roughly eleven weeks, he translated the New Testament from Greek into a German so vivid and standardizing that philologists treat it as a founding document of the modern language. The complete Luther Bible followed in 1534.

What the Reformation changed — and what it cost

Luther intended to reform the Church, not to found one; the split hardened anyway. Within a generation, "Lutheran" churches held much of northern Germany and Scandinavia, while parallel reformations — Zwingli and Calvin in Switzerland, a king's marital politics in England — multiplied Protestantisms Luther often despised. The deeper changes outran theology: worship and Scripture in the vernacular, married clergy, mass literacy as a religious duty, and the precedent — dangerous to every authority — that an individual conscience armed with a printing press could defy pope and emperor and survive.

The costs were immense and are part of the story. The Peasants' Revolt of 1525, partly inspired by reformation rhetoric, was crushed with a brutality Luther loudly endorsed — perhaps 100,000 died. A century of religious wars followed, culminating in the Thirty Years' War. And Luther's own late writings against the Jews — recommending the burning of synagogues — stand among the ugliest texts a major religious founder ever produced, and were eagerly cited by the Nazis four centuries on. He died in 1546 in Eisleben, the town of his birth, still writing, still certain.

Frequently asked questions

Did Martin Luther really nail the 95 theses to a church door?

Possibly, but it isn't certain. The earliest account of the nailing comes from his colleague Philip Melanchthon, written after Luther's death, and Melanchthon wasn't in Wittenberg in 1517. What is firmly documented is that Luther sent the theses to Archbishop Albrecht of Mainz on 31 October 1517 — posting them on the door, the university's usual notice board, would have been routine rather than dramatic.

What's the difference between Martin Luther and Martin Luther King?

Four centuries and an ocean. Martin Luther (1483–1546) was the German monk who started the Protestant Reformation. Martin Luther King Jr. (1929–1968) was the American Baptist minister who led the civil-rights movement; his father, born Michael King, renamed himself and his son in the reformer's honor after a 1934 trip to Germany.

What is an indulgence?

In Catholic theology, a remission of temporal punishment for sins that have already been forgiven — historically earned through prayer, pilgrimage, or charitable works. By Luther's time indulgences were being openly sold, including on behalf of souls in purgatory, and that commerce was his original target. The Church itself banned the sale of indulgences in 1567.