The Marburg Colloquy is the name given to the meeting between Ulrich Zwingli and Martin Luther in 1529. The desired outcome for the meeting was unity within the Protestant world so that it presented a united front to the Catholic Church.
Philip of Hesse wanted to unify all the leading Protestants because he believed that as a divided entity they were vulnerable to Charles V. As a unified force, they would appear to be more powerful. Philip's theory was sound but it failed to take into account one major issue - beliefs.
Luther and Zwingli had corresponded in the early years of the Reformation and they met at Marburg in October 1529. This meeting became known as the Colloquy of Marburg. If Philip wanted the meeting to be a symbol of Protestant unity he was disappointed. Both Luther and Zwingli fell out over the sacrament.
Luther believed that Christ was present at every celebration of the sacrament - though he was never too sure about what happened to the bread and wine in the Mass. Zwingli believed that the communion service was a commemoration of Christ's sacrifices and that the bread and wine were purely symbolic.
Both men clashed over the phrase 'hoc est corpus meum'.
Luther held the view that this meant 'this is my body'. Whereas Zwingli believed it meant 'this signifies my body'. Both men believed that they were right and the meeting only served to demonstrate that the Protestant world was a divided one especially over interpretation. Luther refused to shake hands with Zwingli when he departed and he made his dislike of Zwingli very public. With Luther's standing in northern Germany so high, it is easy to understand why the beliefs of Zwingli did not take root there.