Nicaea

council of Christian bishops in Nicaea, 325

statement of belief adopted at the First Ecumenical Council in 325

successor state of the Byzantine Empire when the crusaders conquered Constantinople at Fourth Crusade of 1204

ecumenical council of the Eastern Orthodox Church and the Catholic Church (787 AD)

Nicaea (also spelled Nicæa or Nicea, ; ), also known as Nikaia (, Attic: , Koine: ) or Nice ( or ), was an ancient Greek city in the northwestern Anatolian region of Bithynia.

1097 The siege of Nicaea

1328–1331 capture of the Byzantine city of Nicaea

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.

queen of Macedonia

daughter of Sangarius in Greek mythology

Unsuccessful attempt by the Umayyad Caliphate to capture the Byzantine city of Nicaea in 727

diocese of the Greek Orthodox Church