ZWINGLI, HULDRYCH (1484–1531), Swiss Protestant theologian. Born in Wildhaus, Switzerland, Zwingli was educated in Vienna (1500–1502) and later in Basel (1502–1506), where he studied under Thomas Wyttenbach. He read Erasmus during his first pastorate in Glarus (1506–1516). During his second pastorate in Einsiedeln (1516–1518), he began to preach against indulgences. In 1518 Zwingli became preacher in the Zurich Cathedral, a post he retained until his death in 1531. He married Anna Reinhart in 1524.

From the beginning of his work in Zurich, Zwingli declared scripture to be the sole ultimate authority for the life and teaching of the church, thereby repudiating hierarchical authority. He preached against indulgences, stating that Christ's sacrifice is sufficient to remit all penalties for sin. He also preached against ascetic religious orders, fasting, the invocation of the saints, and the doctrine of purgatory. As a fervent Swiss patriot, Zwingli opposed Pope Leo X's recruitment of Swiss mercenaries.

In 1522 the civil...