Which figure is considered the most important in spreading Protestantism across Switzerland?

The most important figure in spreading Protestantism across Switzerland is John Calvin. He played a pivotal role in the development of central Protestant theological concepts and established a significant religious community in Geneva that became a center for Protestantism. Calvin's teachings emphasized the sovereignty of God, the authority of Scripture, and the necessity of individual faith, which resonated strongly with many people at that time.

His establishment of a theocratic government in Geneva and the training of ministers who spread his ideas contributed significantly to the growth of Reformed churches in Switzerland and beyond. Calvin's writings, particularly his "Institutes of the Christian Religion," provided a systematic framework for Protestant theology that influenced many regions, not just in Switzerland but throughout Europe.

While Martin Luther was crucial to the wider Protestant Reformation, particularly in Germany, and Ulrich Zwingli was instrumental in initiating the Reformation in Switzerland, it was John Calvin's integration of religious and political life in Geneva that had a substantial and lasting impact on Protestantism in Switzerland specifically. Henry VIII, while notable for his role in establishing the Church of England, was not directly involved in the spread of Protestantism in Switzerland.