Nippur was among the most ancient of Sumerian cities. Nippur was located in modern Nuffar in Afak, Al-Qādisiyyah Governorate, Iraq. Nippur was situated on both sides of the Shatt-en-Nil canal, one of the earliest courses of the Euphrates, between the present bed of that river and the Tigris, almost 160 km southeast of Baghdad. Nippur was the central Sumerian religious authority and sacred city, wielding both power and importance throughout Sumer. The city shows near continuous signs of occupation for almost 6,000 years—from the pre-historic Ubaid period (ca. 5000 BC) until the Islamic era around AD 800.