Nicaea, or Nice, in ancient times, a city of Asia Minor. Now it is the village of Iznik, in Turkey, about 58 mile (93 km) southeast of Istanbul. It was founded in the fourth century B.C. and by Roman times was a large city. Nicaea is best known in history as the site of two important ecumenical councils of the early Christian church, 325 A.D. and 787 A.D.
In 1204, following the capture of Constantinople by Crusaders, Nicaea became the capital of the Empire of Nicaea, one of several successor states to the Byzantine Empire. Nicaea lost its status as an imperial capital in 1262, when its emperor, Michael Palaeologus, captured Constantinople and made that city capital of the reestablished Byzantine Empire. In 1329 Nicaea was conquered by the Ottoman Turks.
The First Council of Nicaea (the church's first ecumenical council) met in 325 A.D. at the call of Emperor Constantine the Great The meeting was held to settle the theological controversy over the nature of Jesus Christ. Arius, founder of Arianism, denied Christ was coeternal with God, contending He was created by God. The church leaders rejected the doctrine as a denial of the Trinity and the council condemned Arius. The council drew up a summary of beliefs that included a precise statement on the Trinity; this summary, with later changes, became the Nicene Creed.
The Second Council of Nicaea (seventh ecumenical council) met in 787. It was held to settle the controversy over images, or icons, begun in 726 when Leo III of the Byzantine Empire ordered all images of religious figures destroyed because he believed they were being worshiped. The council was called by Empress Irene, Patriarch Tarsius of Constantinople, and Pope Adrian I. It declared that icons should be venerated (but not worshiped) and ordered them restored in churches.