Map of religious divisions in the Swiss Confederation (1536)

The Reformation was initially led by Huldrych Zwingli, who gained the support of the population of Zürich in the 1520s. Zwingli, a parish priest in Einsiedeln, began preaching against Church abuses in 1516. He was invited to Zürich in the early 1520s, and his disputation of 1523 led the City Council to accept his reformatory ideas. The state took over the administration of the Church, priests renounced celibacy, and the Church wealth was used to finance social works. 

The Reformation of Zwingli spread to other surrounding cantons, with cities like St Gallen, Basel, Bern and Geneva becoming Protestant. The tension grew with the cantons that remained Catholic; when Zwingli organised a defensive alliance, the Christliches Burgrecht, the Catholic ones responded by forging another with the Hapsburgs of Austria. This led to the first war of Kappel (1529), with Zürich's armies occupying Thurgau and marching against Catholic Zug. The war ended without a battle as mediation resulted in the First Peace (Ersten Landfrieden). 

The peace, however, did not last, with provocations leading to the Second War of Kappel (1531). The five Catholic cantons overwhelmed the Zürich army at Kappel (11 October), and Zwingli himself was killed in the battle. The other Reformed cantons intervened, but were routed. Threatened, Zürich pushed for peace, which was known as the Second Peace (Zweiter Landfrieden). The treaty confirmed each canton's right to practice either the Catholic or Reformed faith, thus defining the Swiss Confederation as a state with two religions. 

Confessional wars did not end then, with two more wars being carried out amongst Catholics and Protestants: in 1656, the First War of Villmergen, led to a reaffirmation of the status quo in the Dritter Landfrieden (Third Peace), while the Second War of Vilmergen (1712) ended with a decisive Protestant victory and major revisions in the Fourth Peace. 

Credit: Georgiana Hedesan (June 2018).