Huldrych (or Ulrich/Ulricht) Zwingli (1 January 1484 – 11 October 1531) was a leader of the Reformation in Switzerland. Born during a time of emerging Swiss patriotism and increasing criticism of the Swiss mercenary system, he attended the University of Vienna and the University of Basel, a scholarly centre of humanism. He continued his studies while he served as a pastor in Glarus and later in Einsiedeln, where he was influenced by the writings of Erasmus.
In 1518, Zwingli became the pastor of the Grossmünster in Zurich where he began to preach ideas on reforming the Catholic Church. In his first public controversy in 1522, he attacked the custom of fasting during Lent. In his publications, he noted corruption in the ecclesiastical hierarchy, promoted clerical marriage, and attacked the use of images in places of worship. In 1525, Zwingli introduced a new communion liturgy to replace the Mass. Zwingli also clashed with the Anabaptists, which resulted in their persecution.