In October 1529, Philip I, Landgrave of Hesse, convoked an assembly of German and Swiss theologians at the Marburg Colloquy, to establish doctrinal unity in the emerging Protestant states. Agreement was achieved on fourteen points out of fifteen, the exception being the nature of the Eucharist – the sacrament of the Lord's Supper—an issue crucial to Luther.
When did Philip I convene an assembly to set doctrine in the Protestant states? Who was Philip I? What was the Marburg Colloquy meant to establish?  How many of the fifteen points of discussion were agreed on? What one point was not agreed on that was dear to Luther?