Zwinglism refers to the teachings and beliefs of Ulrich Zwingli, a Swiss reformer who was a contemporary of Martin Luther during the Protestant Reformation. Zwinglism emphasized the authority of Scripture, rejected certain Catholic practices such as the veneration of saints and the Eucharistic doctrine of transubstantiation, and promoted a more symbolic understanding of the Lord's Supper. His ideas were influential in the development of Protestant theology in Switzerland and beyond.