Martin Luther was born in Eisleben, Germany, the son of Hans Luther, who worked in the copper mines, and his wife Margarethe. He went to school at Magdeburg and Eisenach, and entered the University of Erfurt in 1501, graduating with a BA in 1502 and an MA in 1505. His father wished him to be a lawyer, but Luther was drawn to the study of the Scriptures, and spent three years in the Augustinian monastery at Erfurt. In 1507 he was ordained a priest, and went to the University of Wittenberg, where he lectured on philosophy and the Scriptures, becoming a powerful and influential preacher.

On a mission to Rome in 1510-11 he was appalled by the corruption he found there. Money was greatly needed at the time for the rebuilding of St Peter's, and papal emissaries sought everywhere to raise funds by the sale of indulgences. The system was grossly abused, and Luther's indignation at the shameless traffic, carried on in particular by the Dominican Johann Tetzel, became irrepressible. As professor of biblical exegesis at Wittenberg (1512--46), he began to preach the doctrine of salvation by faith rather than works; and on 31 October 1517 drew up a list of 95 theses on indulgences denying the pope any right to forgive sins, and nailed them on the church door at Wittenberg. Tetzel retreated from Saxony to Frankfurt-an-der-Oder, where he published a set of counter-theses and burnt Luther's. The Wittenberg students retaliated by burning Tetzel's, and in 1518 Luther was joined in his views by Phillipp Melanchthon.

The pope, Leo X, at first took little notice of this disturbance, but in 1518 summoned Luther to Rome to answer for his theses. His university and the elector interfered, and ineffective negotiations were undertaken by Cardinal Cajetan and by Miltitz, envoy of the pope to the Saxon court. The scholar Johann Eck and Luther held a memorable disputation at Leipzig (1519); and Luther began to attack the papal system more boldly. In 1520 he published his famous address An den christlichen Adel deutscher Nation (Address to the Christian Nobility of the German Nation), followed by a treatise De captivitate Babylonica ecclesiae praeludium (A Prelude concerning the Babylonian Captivity of the Church), which also attacked the doctrinal system of the Church of Rome.

A papal bull containing 41 theses was issued against him. He burned it before a multitude of doctors, students, and citizens in Wittenberg. He was excommunicated, and Charles V, Holy Roman Emperor, convened the first Diet at Worms in 1521, before which Luther was called to retract his teachings. Luther refused to relent. An order was issued for the destruction of his books, and he was put under the ban of the Empire. On his return from Worms he was seized, at the instigation of the elector of Saxony, and lodged (for his own protection) in the Wartburg, the elector's fortress. During the year he spent there, he translated the Scriptures and composed his cogent controversial treatise, "Refutation of the Argument of Latomus'.

Civil unrest called Luther back to Wittenberg in 1522. He rebuked the unruly elements, and made a stand against lawlessness on the one hand, and tyranny on the other. In the same year Luther published his acrimonious reply to Henry VIII's attack on him in Assertio septem sacramentorum adversus Martinum Lutherum (1521) about the nature of the seven sacraments.

A divergence had gradually taken place also between the views of the Humanist scholar Erasmus and Luther. There was an open breach in 1525, when Erasmus published De libero arbitrio (1524, Discourse on Free Will), and Luther followed with De Servo arbitrio (Concerning the Bondage of Will). In the same year he married Katherine von Bora, a nun who had withdrawn from convent life.

In 1529 he engaged with the controversial question of transubstantiation in the famous conference at Marburg with Zwingli and other Swiss theologians; he obstinately maintained his view that Christ is present in the bread and wine of the Eucharist. The drawing up of his theological views in the Augsburg Confession (1530) by Melanchthon, ably representing Luther at the Diet of Augsburg, marks the culmination of the German Reformation.

Luther died in Eisleben, and was buried at Wittenberg. Endowed with broad human sympathies, massive energy, manly and affectionate simplicity, and a rich, if sometimes coarse, humour, he was undoubtedly a spiritual genius. His intuitions of divine truth were bold, vivid, and penetrating, if not necessarily philosophical and comprehensive; and he possessed the power of kindling other souls with the fire of his own convictions. His voluminous works include "Von den guten Wercken" (1520, Of Good Works), and "Widder die hymelischen Propheten von den Bildern und Sacrament".