News Archaeology How Asia’s first nomadic empire broke the rules of imperial expansion Ancient China’s mobile neighbors built an empire that’s attracting scientific scrutiny Xiongnu herders in what’s now Mongolia, portrayed in this painting, followed their own rules in building a multiethnic empire and advancing iron-making technology starting around 2,200 years ago, new studies indicate. Flickr (CC0 1.0) Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Bruce Bower July 2, 2023 at 7:00 am In an age that spawned the ancient Roman and Egyptian empires, Mongolia’s Xiongnu Empire broke the rules of imperial expansion.