The nomadic Xiongnu, also known as the Huns, have long been a thorn in China's side. Around the 3rd and 2nd centuries BCE, they united into a powerful confederation of tribes, laying the foundation for a vast steppe empire that threatened China's very existence. Even the construction of fortifications—later evolving into the Great Wall—could not have saved the Middle Kingdom if not for internal conflicts that tore the steppe empire apart from within. Over time, a significant portion of the Xiongnu came under Chinese control and gradually assimilated into its population. However, the northern branch of this people migrated westward at the end of the 1st century CE, absorbing many other tribes along the way. This migration gave rise to the Huns, whose invasions contributed to the fall of the Roman Empire and marked the transition from Antiquity to the Middle Ages in Europe. The history of the Xiongnu is explored in a compelling book by writer Oleg Ivyk and archaeologist Vladimir Klyuchnikov, based on ancient Chinese sources as well as the latest research by modern historians and archaeologists.