At the vanguard of the Reformation, Huldrych (or Ulrich) Zwingli is one of the most radical anti-establishment figures in the whole history of Europe, a dedicated and eloquent humanist who developed a passion for the liberty of individuals to decide the course of their lives free from the strictures of the past. An archetypal “red under the bed” fifth columnist, he used his position of authority in the church to undermine and reinvent the power structures of the church itself. He died at 47 fighting for his cause.

Whereas Zwingli’s contemporary Martin Luther was poorly educated and underwent his internal religious crisis in social isolation, Zwingli came to his personal revolution through education, studying in Basel, Bern, Vienna and possibly Paris, and absorbing the humanist ideas of the Dutch philosopher Erasmus. After ten years as a pastor, his study of scripture led Zwingli to begin questioning the teachings of the Catholic Church; in 1518 he was appointed to the Grossmünster, and began to develop his deeply controversial ideas from the pulpit, proclaiming the sole authority of the word of God as revealed in the Bible, and preaching against church practices. Zürich’s congregation, democratically inclined and politically autonomous, was receptive. Barely a year had passed since Luther had nailed his 95 theses to the door of the Wittenberg church.

In 1523, with mounting tension fuelled by an increasingly vocal opposition to clerical celibacy, monasticism, the observance of Lent and the whole structure of papal control, Zwingli was summoned to a public disputation in Zürich with a papal representative. It says a great deal for Zwingli’s powers of persuasion and the city of Zürich’s courage that, in the historic disputation at a time of religious and political turbulence, the city council came down on the side of their preacher. The papal representative returned to Rome the loser, and mass was celebrated at the Grossmünster for the last time in 1525.

Zwingli’s ideas spread rapidly, and by 1529 Bern, Basel and St Gallen had all embraced the Reformation. Opposition came from two sides: the Anabaptists, who wanted even more radical reform, and the Swiss “Forest Cantons” around Lake Luzern that had taken up arms in loyalty to Rome. War broke out in 1531; Zwingli went into battle but was killed at Kappel. His lead in Zürich was followed by his son-in-law Heinrich Bullinger, but after 1536 the impetus for reform in Switzerland passed to Jean Calvin, a young preacher working in Geneva. Calvin initially followed Zwingli’s doctrine, but soon departed from most of Zwingli’s more radical teachings to develop his own strict theology. Today, thanks in no small measure to the voyages of Calvinist Puritans to the New World, Calvin is much more familiar than his predecessor, but it was the little-known Zwingli who paved the way, forging ideas of personal liberty, and using them to strike at the very heart of the institutionalized hierarchy that had been taken for granted throughout Europe for centuries.