The Eastern Roman Empire and its rival the Sassanid Empire were the most developed states in the Late Antiquity. Using the modern terms of the global world, they can be easily described as ‘superpowers’. The study characterizes both empires from the typological perspective and, simultaneously, attempts to compare Persian and Late Roman societies. Attention is also paid to the comparison of the potential of conscription in both states, to the function and state of the capitals (Constantinople and Ctesiphon), integrative religious doctrine (Christianity and Zoroastrianism) and to relations between secular powers and priests. The final part of the article discusses mutual borders and different strategic targets of both states.