The Reformation in Switzerland began in the early 16th century, primarily led by Ulrich Zwingli in Zurich. Zwingli challenged the Catholic Church's practices and emphasized the authority of the Bible. His ideas spread quickly, leading to the establishment of a Protestant church in Zurich and influencing other Swiss cities. Around the same time, John Calvin emerged in Geneva, further shaping the Reformation with his teachings on predestination and church governance. Calvin's influence extended beyond Switzerland, impacting Protestant movements across Europe. The Reformation ultimately led to significant religious, political, and social changes in Switzerland, resulting in a lasting division between Protestant and Catholic regions.