This paper focuses on the historical development and dynamics of political and administrative structures in regions of a fragmented empire that cannot be simply described as marginal ‘mouseholes’. Rather, it should be acknowledged that these spaces were part and parcel of a wider area (the Byzantine insular and coastal koine), which encompassed coastal areas as well as insular communities promoting socio-economic contact and cultural interchange. More importantly, they also boasted a peculiar set of material indicators suggesting a certain common cultural unity and identity. The koine coincided with liminal territories and the seas on which the Byzantine Empire retained political and naval rulership. Such liminal territories showed varied – yet coherent– administrative infrastructures and political practices on the part of local elites.