Theme of Opsikion Ὀψίκιον, θέμα Ὀψικίου Theme of the Byzantine Empire 640s/660s–1230s Location of Opsician Theme The Asian themes of the Byzantine Empire c. 780 Capital Ancyra, then Nicaea Historical era Middle Ages • Establishment as a theme 640s/660s • Fall to the Latins 1234 Today part of Turkey