Although often mentioned in textbooks about the Carolingian and Byzantine empires, the Treaty of Aachen has not received much close attention. This volume attempts not just to fill the gap, but to view the episode through both micro- and macro-lenses. Introductory chapters review the state of relations between Byzantium and the Frankish realm in the eighth and early ninth century crises facing Byzantine emperors much closer to home, and the relevance of the Bulgarian problem to affairs on the Adriatic. Extensive attention is also given to the local politics of Dalmatia, Venice and the Carolingian marches, and their interaction with the Byzantino-Frankish confrontation.