İznik, formerly known as Nicea, lies at the eastern part of Lake Iznik. İznik, formerly known as Nicea, lies at the eastern part of Lake İznik. The 1st and 7th Ecumenical Councils (is a meeting of the bishops of the whole church to discuss about the matters of Church) were held in Iznik in 325 and 787 A.D., respectively. It was an important Roman and Byzantine town. The city is surrounded by walls about 5 km long. Iznik was a capital of the East Roman Empire when Constantinople was under threat. In 1331, the city was conquered by Ottoman Empire. Iznik became a major center for pottery-making industry in the 17th century (İznik Çinisi). İznik tiles were used by Sinan for many of the mosques in İstanbul.
