[[icoană|icoane]] care erau puse de către [[iconoclasm|iconoclaști]] și a stabilit ca icoanele să fie cinstite.
The first council was held in the “Senatus Palace” that now lays beneath the waters of Lake Iznik. The seventh council was held in the Church of Hagia Sophia that was built by [[Justinian]] in the sixth century, This [[church]] was modeled after the [[Hagia Sophia (Constantinople)|Hagia Sophia]] in Constantinople. Located in the center of the city, Hagia Sophia was turned into a mosque by the Turks and renamed Orhan Ghazi Mosque in 1331. Over the years this structure has been badly damaged by earthquakes and fires. Some mosaics and a fresco of Christ, however, remain. The Church of the Dormition, a major church in Nicea, was destroyed by the Turks in 1922. This church was decorated with many fine mosaics that dated from the ninth century.
In 1081, Nicea was captured by the Seljuk Turks, but was recaptured in 1097 by Emperor Alexius I Comnenus. During the period that the Turks held Nicea, they renamed the city Iznik. When Constantinople was captured by the Latin Crusaders in 1204, the Byzantine Romans established separate realms in the parts of Anatolia that were not held by the Latins. Nicea became the capital of the “Empire of Nicea” and served for 50 years as the political and cultural center of this the strongest of the Byzantine states until Michael VIII Palaeologus recaptured Constantinople from the Latins and restored Byzantium. In 1331, the Ottoman Turks captured Nicea, again renamed the city Iznik. After the Turks captured Constantinople in 1453, the prosperity of the city fell under the competition from Turkish Constantinople.