States and territories disestablished in 1234

Jurchen dynasty that ruled in northern China 1115–1234 and its eponymous empire

The Opsician Theme (, thema Opsikiou) or simply Opsikion (Greek: , from ) was a Byzantine theme (a military-civilian province) located in northwestern Asia Minor (modern Turkey). Created from the imperial retinue army, the Opsikion was the largest and most prestigious of the early themes, being located closest to Constantinople. Involved in several revolts in the 8th century, it was split in three after , and lost its former pre-eminence. It survived as a middle-tier theme until after the Fourth Crusade.