The Principality of Achaea in Dire Straits: The Byzantine Campaign of 1263/64 as Prelude to the Morea’s Submission to the Angevins

Abstract In the aftermath of the Fourth Crusade and the conquest of Constantinople in 1204, a number of Latin polities were established in former Byzantine territories. Among them, the Principality of Achaea emerged as one of the few Latin states to achieve relative longevity within the fluid and contested geopolitical landscape of the Eastern Mediterranean. Its continued existence, however, increasingly relied on the support of the Angevin monarchy of Sicily. This dependence was, in part, a consequence of the renewed Byzantine efforts to reclaim lost territories – most notably the 1263 campaign initiated by Emperor Michael VIII Palaiologos, whose objective was the reassertion of imperial authority over the Peloponnese, known in Byzantine sources as the Morea. This study seeks to demonstrate, through close textual analysis and a comparative examination of narrative and documentary sources, that the aforementioned campaign played a decisive role in consolidating the Principality of Achaea’s dependency on Angevin suzerainty.