Passage: In 1519, Zwingli became the pastor of the Grossmünster in Zürich where he began to preach ideas on reform of 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.  Historians have debated whether or not he turned Zürich into a theocracy.The Reformation spread to other parts of the Swiss Confederation, but several cantons resisted, preferring to remain Catholic. Zwingli formed an alliance of Reformed cantons which divided the Confederation along religious lines. In 1529, a war between the two sides was averted at the last moment. Meanwhile, Zwingli's ideas came to the attention of Martin Luther and other reformers. They met at the Marburg Colloquy and although they agreed on many points of doctrine, they could not reach an accord on the doctrine of the Real Presence of Christ in the Eucharist.

Question: In what year was a conflict narrowly avoided?
1529