Commonwealth of the islands
Confederation of the Aegean islands. The initiative for its establishment is attributed to Antigonos the One-Eyed and is dated to 313 BC. The Commonwelth, which seems to have been put under the protection of the sanctuary of Apollo in Delos, allowed Antigonos to control the islands and to use them as bases for the spread of his power in mainland Greece. Outside Apollo's cult, within the framework of the Commonwelth there were instituted cults in honour of the house of Antigonidae and later the Ptolemies.

theme
A Byzantine term that signifies wide military and administrative units under the administration of a strategos (general). The institution was consolidated in the 7th century and was characteristic for the organization and the division of Byzantine Empire at the Middle Byzantine period. The term applies also to the army unit that resided in each administrative unit and was staffed by farmer-soldiers. The thematic system was maintained until the end of Byzantine period. However, in the Later Byzantine period it was used in order to declare mostly tax units.