A graph superimposes the growth–decline curves of major Stirrup Rider Empires, from 600 to 1200. While being a major advance in horse riding, the stirrup just offers a short term for the intermediary phase of Rider Empires. Expansion of Islamic Caliphate was the towering event. It surpassed the Xiongnu area record. Apart from Tang, Tufan in Tibet, Liao, and Seljuk, all other medieval empires remained of modest size. In population, Song in 1125 briefly reached 38% of the world population – the largest percentage any empire has ever reached. The Caliphate altered the language mix throughout North Africa, introducing the Arabic. The Seljuks did so from Central Asia to Anatolia, introducing Turkic. The Caliphate clashed with Tang in Central Asia in 751. The forces of an empire reaching to the Atlantic Ocean confronted for the first time those of an empire that reached to the Pacific. Neither realized the momentousness of this skirmish. Western Europe developed feudalism, a maddeningly complex multistranded hierarchical order, which does away with single territorial authority.

This chapter deals with empires created by Turkic-speaking peoples in Western Eurasia between c.500 and 1200. It focuses on the empire of the Seljuk Turks and the Mongol Empire. Although vast in size, most Turkic polities were very short-lived. All empires were torn between the desire to centralize rule and the need to manage their multitude of different peoples. Generally, rulers that tried to impose a centralized, top-down order and break the power of local aristocratic orders soon saw their empires fail. Similarly to medieval Europe, successful rulers managed the multitude of sub-rulers and peoples by accepting a looser form of empire. Eventually, the steppe polities disintegrated because of their lack of embedding institutions. These findings support my argument that successful polity formation seems to hinge on developing political forms based on negotiation and shared rule – a pattern visible in Europe but not in the Middle East.