Frederick III, Elector of Saxony, remembered as ‘the Wise’, died 500 years ago this month. He had a supporting role in the history of the early Reformation as the patron and protector of Martin Luther: from 1518 to his death in 1525, the shield Frederick provided was vital, but the man himself tends to be relegated to footnotes, merely a cog in the machine. There was more to him than that.

Frederick was 23 when he succeeded his father Ernest as Elector of Saxony in 1486. The previous year, the Treaty of Leipzig had split the lands of the House of Wettin, Frederick’s father receiving Electoral Saxony as the Ernestine branch, and younger brother Albert ruling Ducal Saxony and founding the Albertine line.

As one of the seven Electors of the Holy Roman Empire, Frederick was part of the Electoral College that chose the emperor. The incumbent, another Frederick III, was in his 70s, and during his long reign had consolidated the power of his family, the Habsburgs, as a major force in central Europe. A few months before the Saxon Frederick had succeeded his father as Elector of Saxony, the emperor’s only son, Maximilian, had been elected King of the Romans, the title of the heir to the Holy Roman Empire, securing the immediate future of the empire for the Habsburgs.

Germany in the 15th century was a shifting network of perhaps 2,000 states and cities. The emperor was the senior temporal ruler in Europe, but could only exert authority by virtue of the territories he held personally; the Habsburg centre of power was Austria, to which Maximilian’s advantageous marriage had added the prosperous Netherlands.

Electoral Saxony was a significant player: its wealth came from regalian rights over mining, coinage, tolls and salt, fees for the administration of justice, and taxes. It also benefitted from the convergence of trade routes from across Europe and hosted profitable international fairs and markets.

Frederick was pious but conventional, reformist in his approach to efficient government and conscious of the reputation of his state. It was that last consideration which motivated him to found a university in his capital of Wittenberg in 1502. He had begun restoring Wittenberg Castle as his principal residence, and was building a new Late Gothic Schlosskirche, All Saints’ Church, attached to it.

The university was important in an age of burgeoning scholarship and culture. The empire had been slow in this respect, with the University of Prague being founded only in 1348, by which time Bologna and Oxford had been teaching for more than 250 years. By Frederick’s time, there were perhaps 15 universities within the empire, one of them at Leipzig in the territory of his cousin, Duke George of Saxony. The situation was intolerable.

Wittenberg was founded with an intake of 416 students. The first rector was Frederick’s personal physician, Martin Pollich, but another key figure was the Dean of the Faculty of Theology, Father Johann von Staupitz, an Augustinian friar from Tübingen. With Staupitz came a number of other Augustinians, including some teachers from the University of Erfurt.

In 1508, Staupitz sought more recruits from Erfurt. One of them was a young, recently ordained friar, Martin Luther. He was a diligent and able scholar who lectured on Aristotle’s Ethics, and, after returning to Erfurt, came back to Wittenberg in 1512. He was awarded his doctorate in theology, and succeeded Staupitz as Professor of the Bible.

Luther’s lectures on Scripture concealed a growing spiritual crisis over the doctrine that good works, rather than faith in God alone, contributed to salvation. He was also increasingly hostile to the selling of indulgences, by which sinners could earn some remission from punishment for their sins. His doubts erupted in 1517 when he (so it is said) nailed his 95 Theses to the door of the Schlosskirche in Wittenberg. These arguments spread rapidly, thanks to the growing availability of print, and in 1518 Pope Leo X summoned the renegade friar to Rome to answer charges of heresy.

It was then that Frederick intervened. He was in no sense a proto-Protestant: he was an avid collector of relics, with nearly 20,000 items in the Schlosskirche to which people could pray for remission of their for sins. Ironically, the sale of indulgences had contributed to the foundation of the University of Wittenberg. But Luther was by now a star on a European scale, and he was Wittenberg’s star. The elector would not countenance his cross-examination by foreign clerics at the Curia.

Frederick persuaded the Pope that Luther should be interrogated at the Reichstag, the imperial parliament, that October in Augsburg. For three days, Luther debated with the papal legate, Thomas Cardinal Cajetan, on the Pope’s authority to issue indulgences, insisting that the Pope was not above Scripture. He would not recant, but slipped out of the city to evade arrest. In July 1519, he clashed at a public disputation in Leipzig with Johann Eck of the University of Ingolstadt, his cause initially fought by the Dean of Theology at Wittenberg, Andreas Karlstadt. Again, Luther would not back down.

This was now a grave matter. In June 1520, Leo X issued the bull Exsurge Domine, in which he warned Luther that he would be excommunicated if he did not recant 41 propositions in his work. Not only would Luther not recant: in December, in front of a crowd at Wittenberg’s Elster Gate, he burned the papal document. On 3 January 1521 he was excommunicated by the bull Decet Romanum Pontificem. The papal gloves were off.

The Reichstag met again in 1521 at Worms, and the Emperor Charles V, who had been elected to succeed his grandfather Maximilian in 1519, summoned Luther once more. Frederick insisted on safe passage to and from the Reichstag, and the emperor was in his debt. Charles and the French king, Francis I, had spent vast sums bribing the electors, who were reluctant to support either of the non-German candidates; it is said that they approached Frederick as a compromise choice. He refused, and Charles was elected unanimously.

The outcome of the showdown at Worms is well known. Eck again questioned Luther, culminating in the defiant declaration ‘Hier stehe ich, ich kann nicht anders’. In response, the emperor issued the Edict of Worms, which declared Luther a heretic, proscribed his writings and placed him under the Reichsacht, the imperial ban, making him an outlaw who could be killed without legal consequences.

Again, Frederick intervened to protect Luther. He arranged for him to be intercepted on his return journey to Wittenberg and taken to the Wartburg, a castle overlooking Eisenach, where Luther took refuge for 10 months, producing a torrent of polemic and translating the New Testament into German. He returned to Wittenberg in 1522, where Karlstadt had introduced reformed religious practice, which Luther thought had gone too far.

Luther was still not safe, but the greatest danger had passed. The Reichstag met at Nuremberg in 1522 and, while the papal legate demanded action against Luther, the German princes were unwilling to oppress ‘evangelical truth’ and looked to the Church to reform itself. Another assembly in 1524 made it clear that there was no appetite on the Reichstag’s part to pursue Luther.

Frederick died in May 1525, aged 62. His protection of Martin Luther at that critical period between the Reichstag meetings of 1518 and 1522 may have saved the Protestant Reformation. A month before he died, on Palm Sunday, the elector had attended Mass in Wittenberg and heard the service in German for the first time. Yet he remained a Catholic prince, though on his deathbed he received communion under both kinds, both bread and wine, which the Church forbade for the laity but Luther championed.

How do we explain Frederick the Wise? Here was a man who made a pilgrimage to Jerusalem in 1493; who collected, publicly displayed, and prayed to 19,013 relics, including the thumb of St Anne, a twig from the Burning Bush, and breast milk from the Virgin Mary; and who used the profits from selling indulgences to fund his university. If he did accept any kind of Protestantism, it was hours before his death.

Frederick’s piety was not incompatible with other forces which were at work, namely a sense of political autonomy and desire for justice. Luther might be a theological provocateur, but he was Saxony’s most famous scholar and preacher, one of the most notable men in Europe. The elector refused to submit wholly either to papal or imperial supremacy in determining Luther’s fate.

He also wanted to see due process observed. He was unconvinced that the pursuit and outlawing of Luther was the correct response to asking questions about a Church that was clearly in need of change, as Pope Adrian VI had conceded by 1522. Fundamentally, he was a reformer, as he showed in the governance of Saxony and his support for modernising the imperial government. His establishment of Wittenberg demonstrated his attachment to scholarship and study. None of this sat easily with the brutal certainty of the Edict of Worms or the imperial ban.

‘Such a prince is a blessing from God’, Luther wrote after Frederick’s death. The Elector of Saxony did not set out to save or nurture the Protestant Reformation, but, like any political actor, took decisions day-by-day according to calculations made and remade. The two men probably never met, and certainly were not kindred spirits, but it was Frederick more than anyone else who ensured that Luther did not become yet another medieval heretic dying a martyr’s death, but a man who changed the world.