Modun

Modun Chanyu, also spelled Modu, was a Xiongnu ruler who became one of the most prominent leaders of the Xiongnu confederation in the late 3rd century BCE. He is traditionally dated to have reigned circa 209–174 BCE. Modun is credited with transforming the Xiongnu from a loose tribal federation into a centralized state, establishing the chanyu as supreme ruler, and reorganizing political and military institutions to support sustained campaigns.

Under his leadership, the Xiongnu expanded their authority across the northern steppe and into adjacent regions, subjugating rival groups and building a formidable cavalry-based military. The expansion increased the Xiongnu's influence and brought them into frequent contact and conflict with neighboring polities.

This growth intensified tensions with the Han dynasty of China, contributing to a period of border warfare and shaping Han foreign policy toward deterrence, diplomacy, and periodic negotiations with nomadic powers. The exact details of Modun’s campaigns vary among sources, but his reputation rests on the claim that he established a centralized, durable Xiongnu state.

Modun's reforms are considered foundational for later Xiongnu power and influenced steppe politics for generations. Much of what is known about him comes from Chinese historical texts, including works such as the Records of the Grand Historian and the Book of Han, which describe his role in unifying and strengthening the Xiongnu state.