Ancient Nicaea, located in present-day Turkey, was an important city in the region of Bithynia. It is best known for hosting the First Council of Nicaea in 325 AD, which was convened by Emperor Constantine to address issues within early Christianity, including the Arian controversy. The council produced the Nicene Creed, a statement of Christian faith that is still used today. Nicaea was also a significant center for trade and culture in antiquity. Its strategic location near Lake Ascania made it a hub for travelers and merchants. The city was fortified with walls and featured notable structures, including temples and public buildings, reflecting its historical importance.