Opsikion

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.

==History== The Opsician theme was one of the first four themes, and has its origin in the praesential armies of the East Roman army. The term Opsikion derives from the Latin term ("retinue"), which by the early 7th century came to refer to the units escorting the emperor on campaign. It is possible that at an early stage, the Opsikion was garrisoned inside Constantinople itself. In the 640s, however, following the disastrous defeats suffered during the first wave of the Muslim conquests, the remains of the field armies were withdrawn to Asia Minor and settled into large districts, called "themes" (themata). Thus the Opsician theme was the area where the imperial Opsikion was settled, which encompassed all of north-western Asia Minor (Mysia, Bithynia, parts of Galatia, Lydia and Paphlagonia) from the Dardanelles to the Halys River, with Ancyra as its capital. The exact date of the theme's establishment is unknown; the earliest reference points to a creation as early as 626, but the first confirmed occurrence is in 680. It is possible that it also initially included the area of Thrace, which seems to have been administered jointly with the Opsikion in the late 7th and early 8th centuries.