Genghis Khan unites the Mongol tribes and launches a campaign of conquest that, under his descendants, pushes from the Asian steppe all the way to the edges of modern Germany. This episode of the Barbarians series traces that expansion through large-scale battle reenactments mixed with historian commentary, covering the mounted archery, siege tactics, and rapid movement that let a nomadic army overrun settled empires far larger than itself. It sits inside a broader series built around warrior cultures that clashed with Rome and its successors, but here the focus stays on the Mongols specifically: their organization under Genghis Khan, the machinery of conquest his sons and grandsons inherited, and the reputation for savagery that followed them across Asia and into Europe. The reenactments carry most of the storytelling, staging cavalry charges and city sieges rather than relying on narration alone. It is a fast-moving account of how one confederation of horsemen reshaped the map of two continents in a single century.