Native Sumerian rule re-emerged for about a century in the Neo-Sumerian Empire or Third Dynasty of Ur (Sumerian Renaissance) approximately 2100-2000 BC, but the Akkadian language also remained in use. The Sumerian city of Eridu, on the coast of the Persian Gulf, is considered to have been the world's first city, where three separate cultures may have fused — that of peasant Ubaidian farmers, living in mud-brick huts and practicing irrigation; that of mobile nomadic Semitic pastoralists living in black tents and following herds of sheep and goats; and that of fisher folk, living in reed huts in the marshlands, who may have been the ancestors of the Sumerians.