The peace concluded after the First War of Kappel two years earlier had prevented an armed confrontation, but the tensions between the two parties had not been resolved, and provocations from both sides continued, fuelled in particular by the Augsburg Confession of 1530.

The Protestant canton of Zürich and Huldrych Zwingli, leader of the Swiss Reformation, feared a military action by Ferdinand I, Archduke of Austria and his brother Charles V, Holy Roman Emperor against Swiss Protestants, and saw the five Catholic cantons of Central Switzerland (Lucerne, Schwyz, Uri, Zug and Unterwalden) as potential allies of the two Habsburg sovereigns.

Between 15 and 21 October, a Protestant army, vastly outnumbering the enemy force, marched through the Reuss valley up to the entrance of Baar, and the Catholic troops withdrew to the Zugerberg.

[1] From the beginning of November, representatives of the cantons that remained neutral: (Solothurn, Freiburg, Glarus and Appenzell), as well as French diplomats, had been trying to mediate a peace settlement.

Only strategically important places such as the Freiamt or those along the route from Schwyz to the Rhine valley at Sargans (and thus to the alpine passes in the Grisons) were forcibly re-Catholicised.

In both the territories of Thurgau and Aargau, for example, Catholic and Protestant congregations began worshiping in the same churches, which led to further tensions and conflicts throughout the sixteenth and seventeenth centuries.

The treaty also confirmed each canton's right to practice either the Catholic or Reformed faith, thus defining the Swiss Confederation as a state with two religions,[2] a relative exception in Western Europe.

[1] An unsuccessful effort by the Protestant cantons, especially Zürich, to change the terms of confessional coexistence in 1656, the First War of Villmergen, led to a reaffirmation of the status quo in the Dritter Landfrieden (Third Territorial Peace).