Answer
Zwingli and Luther met at the Marburg Colloquy in 1529, where they discussed their differences in beliefs. The two men agreed on most doctrines, such as the importance of faith and Scripture, but they disagreed on the Eucharist. Luther believed that the bread and wine in the Eucharist literally became the body and blood of Christ, while Zwingli believed that they were only symbols of Christ's body and blood.