Huldrych Zwingli (1 January 1484 - 11 October 1531) was a Swiss priest and theologian whose preaching and writing in Zürich from 1519 onward established Reformed Protestantism as a distinct branch of the Reformation, separate from Lutheranism. He is regarded, alongside Martin Luther and John Calvin, as one of the principal founders of Protestantism, and his theological method-particularly his approach to scripture, the sacraments, and the relationship between church and civil government-shaped the Reformed tradition that spread through Switzerland, parts of Germany, and later into the Anglo-American world. Some aspects of his career and theology, including his break with Luther over the Eucharist and his role in the political and military conflicts of the Swiss Reformation, remain subjects of differing interpretation among historians and theologians; see huldrych-zwingli-eucharist-viewpoint-debate and huldrych-zwingli-controversy.

Zwingli was born in Wildhaus, in the Toggenburg region of the Swiss Confederacy, and educated at Basel, Bern, Vienna, and Basel again, where he was influenced by humanist scholarship, including the work of Erasmus. Ordained a priest in 1506, he served parishes in Glarus and Einsiedeln before becoming people's priest at the Grossmünster in Zürich in 1519. There he began preaching systematically through books of the New Testament rather than following the standard lectionary, a method that became a hallmark of Reformed preaching. Over the following decade he led the city council and citizenry of Zürich through a series of reforms-abolishing the Mass, removing images from churches, ending clerical celibacy, and restructuring church governance under civic authority-that became a model for other Swiss cities. His career and the broader political context of the Swiss Reformation are addressed at greater length in huldrych-zwingli-history.

Historians and theologians generally agree on the basic chronology of Zwingli's career and his central role in establishing the Reformed wing of the Reformation, distinct from both Roman Catholicism and Lutheranism. Areas of ongoing scholarly discussion include the precise sources and originality of his theology relative to humanism and to Luther, the nature and extent of his political involvement in the Swiss Confederacy's internal conflicts, and the proper characterization of his sacramental theology, particularly regarding the Eucharist. His death at the Battle of Kappel in 1531 raises questions of interpretation given his clerical office; see huldrych-zwingli-kappel-controversy.

• Reformed/Zwinglian Eucharistic viewpoint: Holds that Zwingli's interpretation of the Lord's Supper as a memorial and symbolic act, rather than a site of Christ's physical or substantial presence, represents a theologically coherent and scripturally grounded position distinct from both Catholic and Lutheran views. See huldrych-zwingli-eucharist-viewpoint.
• Lutheran critical viewpoint: Holds that Zwingli's rejection of a real presence in the Eucharist constituted a serious theological error that justified Luther's refusal to recognize full fellowship with the Swiss reformers. See huldrych-zwingli-lutheran-critical-viewpoint.
• Magisterial Reformation viewpoint: Regards Zwingli as a co-founder, alongside Luther and later Calvin, of a Reformation conducted in partnership with civil authorities, emphasizing continuity between his reforms and the broader magisterial Protestant project. See huldrych-zwingli-magisterial-reformation-viewpoint.
• Radical Reformation critical viewpoint: Associated with early Anabaptist critics, some of whom were originally Zwingli's own associates in Zürich, this viewpoint holds that Zwingli's reforms did not go far enough, particularly in retaining civil enforcement of religion and infant baptism. See huldrych-zwingli-radical-reformation-critical-viewpoint.
• Catholic critical viewpoint: Holds that Zwingli's reforms constituted an unlawful break from apostolic church authority and sacramental tradition, and characterizes his political and military involvement as evidence of the disorder introduced by the Reformation. See huldrych-zwingli-catholic-critical-viewpoint.

• Zwingli's death at the Battle of Kappel: Disputes exist over how to characterize a priest and city reformer dying in armed combat, and over the political decisions in Zürich and the Swiss Confederacy that led to the battle. See huldrych-zwingli-kappel-controversy.
• The Marburg Colloquy and the Lutheran-Reformed split: The 1529 meeting between Zwingli and Luther failed to resolve their disagreement over the Eucharist, an outcome with lasting consequences for Protestant unity that is itself a matter of historical and theological dispute. See huldrych-zwingli-marburg-colloquy-controversy.

• huldrych-zwingli-history
• huldrych-zwingli-eucharist-viewpoint-debate
• huldrych-zwingli-eucharist-viewpoint
• huldrych-zwingli-lutheran-critical-viewpoint
• huldrych-zwingli-magisterial-reformation-viewpoint
• huldrych-zwingli-radical-reformation-critical-viewpoint
• huldrych-zwingli-catholic-critical-viewpoint
• huldrych-zwingli-kappel-controversy
• huldrych-zwingli-marburg-colloquy-controversy
• Protestant Reformation
• Calvinist-Lutheran Eucharist - Overview
• Protestant Reformers

1. George R. Potter, *Zwingli* (Cambridge: Cambridge University Press, 1976).
2. W. P. Stephens, *The Theology of Huldrych Zwingli* (Oxford: Clarendon Press, 1986).
3. Bruce Gordon, *The Swiss Reformation* (Manchester: Manchester University Press, 2002).
4. Ulrich Gäbler, *Huldrych Zwingli: His Life and Work*, trans. Ruth C. L. Gritsch (Philadelphia: Fortress Press, 1986).
5. Diarmaid MacCulloch, *The Reformation: A History* (New York: Viking, 2003).