This essay explores the challenges of supply faced by Byzantium as it conducted campaigns against a formidable array of enemies in a variety of circumstances over the course of a millennium. Although one may quibble about dates, the most reasonable point for the beginning of Byzantine logistics was the creation of a seat of imperial government at the former city of Byzantium, now renamed Constantinople, by Emperor Constantine I in 330. That act created a new set of strategic realities with important effectson military transportation and communications; it marks the beginning of the early Byzantine period (A.D. 330-610). The seventh century brought a transition to the middle Byzantine period (610-1025), a distinctly different era in logistics, as the empire readjusted to enormous territorial losses to the Muslims, Avars, and Slavs, and to a lesser extent, to some of the Germanic kingdoms (especially to the Visigoths and Lombards). The principal scope of this essay is the early and middle Byzantine periods, because in the final or late Byzantine period (1025-1453), and especially after 1300, the empire faced diminishing strategic depth and multiple threats, which made its logistical situation a nightmare for anyone attempting to construct a viable defense of the empire.