The term "Xiangnu" refers to a group of nomadic tribes that inhabited the region of modern-day Mongolia and northern China during ancient times. They were known for their horse-riding skills and played a significant role in the history of the Silk Road, engaging in trade and conflict with neighboring states, including the Han Dynasty. The Xiangnu were often in conflict with the Han, leading to military campaigns and diplomatic efforts. Their society was organized into clans, and they practiced a form of pastoralism, relying on livestock for sustenance. The decline of the Xiangnu began around the 1st century CE, as they fragmented into smaller groups.