Abstract
In his honest desire to reform the Catholic Church, Martin Luther looked up sometimes to Eastern Christianity and its Ancient Fathers. Especially in the context of his debates with Catholic theologians, Luther tried to accomplish a theological norm through quotes and arguments from the spiritual thesaurus of the Eastern Church. In spite of the fact that Luther‘s references to the Eastern Church show a certain ambiguity and are not as extensive as one would wish today, these are of particular importance and carry undeniable weight for the Reformation period and the Reformers’ knowledge of Eastern Christianity. Luther’s mentions of the Eastern Church constitute until today the basic points of modern ecumenism between Protestantism and Orthodoxy.