The unified Chinese Empire, which was born in the 3rd century BC, came under serious threat soon after its establishment. The Asian Huns (Xiongnus), who had harassed the former northern principalities for a century and then pushed north in the Chinese campaigns of 210 BC, were replaced in 209 BC by a new leader, Modu (Maodun), who soon established the first East Asian Steppe Empire.
The remains of a Sumerian palace have been discovered by archaeologists in the ancient city of Girsu, Iraq, in the Dhi Qar governorate. The remains date back 4,500 years, meaning that they can be traced back to the third millennium BC.