  We have tried to impose a provisional borderline between Byzantine philosophy and other areas which are so closely related to Byzantine philosophy as to be sometimes inseparable from it. Most importantly, we have tried to demarcate our subject matter from that of Byzantine theology, not because we believe that an account in which the religious dimension is largely ignored will be sufficient to grasp Byzantine intellectual history in its organic entirety, but because we think that a clearer conception of the “purely” philosophical part of Byzantine intellectual history is both desirable in itself and necessary for the understanding of the whole. This may seem to lead us straight towards an episodic account, concentrating on a few solitary thinkers on the fringe of Byzantine intellectual history. In order to avoid this we have chosen not to place very heavy demands on the originality of the works to be included. Our main concern has been to describe the typical features of the philosophical tradition in Byzantium, rather than to highlight the rare instances when innovative views and arguments were put forward. For further discussion of the methodology of the history of Byzantine philosophy, see Kapriev (2006), Trizio (2007), Golitsis (2011), and Gutas and Siniossoglou (2017).