Circa 2nd century BCE, the Tibeto-Burman-speaking Pyu people began to enter the Irrawaddy River Valley from present-day Yunnan using the Taping and Shweli Rivers. The original home of the Pyu is reconstructed to be Qinghai Lake, which is located in the present-day provinces of Qinghai and Gansu. The Pyu, the earliest inhabitants of Burma of whom records are extant, went on to found settlements throughout the plains region centred on the confluence of the Irrawaddy and Chindwin Rivers that has been inhabited since the Paleolithic. The Pyu realm was longer than wide, stretching from Sri Ksetra in the south to Halin in the north, Binnaka and Maingmaw to the east and probably Ayadawkye to the west. The Tang dynasty's records report 18 Pyu states, nine of which were walled cities, covering 298 districts.