Martin Luther

Even as a monk he was troubled for years by the fear that he might not be saved. Teaching the Bible at the University of Wittenberg and reading the letters of Paul again and again, he came to the conclusion that a person is accepted by God through faith rather than by piling up good deeds. That idea became the root of everything else he argued.

At that time the Church was selling indulgences to help pay for the building of St Peter's Basilica. An indulgence was a certificate said to reduce the punishment owed for one's sins, and the preachers who sold them went so far as to say that 'as soon as the coin in the coffer rings, the soul from purgatory springs.' On 31 October 1517 Luther wrote out ninety-five theses setting out why this was wrong and circulated them among churchmen and scholars. The famous scene of him nailing them to the door of the castle church at Wittenberg comes from later accounts and is still debated; what is certain is that the printing press, then newly widespread, carried his words across Germany within weeks.

The dispute soon grew into a question about the authority of the whole Church. When the pope sent a document in 1520 warning him to take back his claims, Luther burned it in public, and the following year he was excommunicated — expelled from the Church. Summoned in 1521 before Emperor Charles V and the princes at the Imperial Diet in Worms, he refused to recant: 'My conscience is captive to the Word of God. I cannot and will not recant.'

The emperor then placed him outside the protection of the law. Frederick, Elector of Saxony, who valued him, staged a kidnapping and hid him in Wartburg Castle, where Luther grew a beard, passed himself off as 'Knight George' and stayed for ten months. There he translated the Greek New Testament into German in eleven weeks, choosing words ordinary people actually used; that translation is credited with shaping the German language ever since. Legend says that when the devil appeared one night to disturb his writing, Luther hurled his inkpot at him — and visitors are still shown the stain said to be on the wall.

The door he opened let through things he had not expected. When German peasants rose in 1525 demanding relief from heavy burdens, Luther sympathised with their hardships but rejected their violence and urged the princes to put the revolt down. Tens of thousands died, he lost the trust of the peasants, and this remains the most disputed episode of his life. In the same year he married Katharina von Bora, a former nun, and they had six children — a household that offered a new model of what a married clergyman's family could look like.

Luther wrote music as well. His hymn 'A Mighty Fortress Is Our God' became a song of the Protestant lands, and a century later the soldiers of King Gustavus Adolphus of Sweden are said to have sung it before battle in the Thirty Years' War. In his last years, however, he wrote harsh tracts against Jews that did great harm afterwards, and these are remembered today as the dark side of his legacy.

In 1546 Luther travelled back to his birthplace, Eisleben, to help settle a quarrel between local lords, fell ill and died there. Nine years later the Peace of Augsburg recognised the Lutheran faith on the principle that a ruler's religion was the religion of his land — but the Calvinists, who had spread later, were left out of it. That gap, together with the growing rivalry between princes divided by faith, built up until it broke out as the Thirty Years' War in 1618.