Iznik, formerly known as Nicea, lies by the lake with the same name. Originally an important Roman and Byzantine town. It bears exceptional witness to the introduction and early expansion of Christianity. The town hosted 1st and 7th Ecumenical Councils. The St.Sophia Cathedral in the town centre is the seat of the first Ecumenical Council. It fell to the Seljuks in 1078 and subsequently to the Ottomans in 1331. In the 16th and 17th centuries, İznik gained importance because of its beautiful ceramic products and especially tiles that is famous all over the world.