This research group studies the specific character and meaning of the ancient philosophical tradition and the special source tradition of this field. Research questions are: What is the nature of ancient philosophical problems and systems when analysed and explicated in their own intellectual and cultural context? What is the nature of our sources for ancient philosophy and how does the nature of the transmission and reception affect the interpretation of ancient philosophical texts? The group works along two main lines: It studies ancient philosophical literature on the basis of its sources, with due attention to the transmission of these sources and its relevance for philosophical interpretation. This approach is clearly differentiated from the analytical/philosophical method that has conquered the Anglo-Saxon world - a method that tends to discuss questions and philosophers in an a-historical way. The group aims at achieving an interpretation that fully takes into account the intellectual, historical and cultural context. The philosophical analysis of this material involves more than a narrowly philological interpretation: the historian of philosophy analyses texts not only in order to fit them into the historical development of philosophical problematics and systematics, but also because (s)he is concerned with fundamental philosophical problems that retain their actuality throughout the long tradition of Western philosophy.