The goal of this article is to focus on one of the possible lines for analyzing ‘Byzantium’ as a political tool throughout the centuries. Its starting point will be what is most likely the first explicit use of the dissolved Empire of Constantinople to promote coeval politics, during the reign of Louis XIV. The end point of our account will be the suppression of the Kondakov Institute in Prague, probably the most influential center for Byzantine studies, between the two World Wars. Our investigation will, however, not follow a chronological order. As suggested by the paper’s subtitle, we will try to analyze how the very notion of ‘Byzantium’ has been used by scholars and policymakers as a tool for promoting national, colonial, and ‘global’ constructions of the world.