From the founding of imperial China in 221 B.C.E. until the eighteenth century the nomadic peoples of Inner Asia posed the strongest challenge to regimes in China. The Tang dynasty (618-907) developed effective policies to handle these competitors during the first half of its rule. Some scholars have proposed that by adopting strategies of appeasement Chinese dynasties normally encouraged the growth of parasitic nomadic confederations. This was not the case in the first half of the Tang. Using a mixture of accommodational, coercive, and defensive strategies, the Tang kept nomads relatively divided and weak. The Tang's policies were effective because they broke the cultural boundaries conventionally assumed to exist between Inner Asia and China. This was possible because a multi-ethnic society and hybrid political culture had developed in North China after nomadic conquests in the preceding centuries.
    Politically, the dynasty created a new ideology of the "Heavenly Qaghan" that Tang emperors used to compete with Inner Asian chiefs for the loyalty of nomads. By offering rewards, protection, marriages, and trade, the Tang rulers won over nomadic groups and strengthened the dynasty at the expense of competing chiefs on the steppe. When nomads could not be controlled through peaceful means, the Tang relied upon coercive and defensive measures. Diplomacy and subterfuge were utilized to exploit conflicts within hostile tribes or to create alliances to fight against them. In warfare the Tang gained parity with the militarily adept steppe nomads by adopting the light cavalry common in Inner Asia and recruiting skilled Chinese and non-Chinese mounted archers to serve in their forces. The Tang's cavalry was the key to their ability to counterattack against invaders and launch campaigns on the steppe.
    Although the Tang's hybrid cultural background played a large part in implementing these effective Inner Asian policies, two other factors were important. One was the availability of strong emperors and talented civil and military personnel. The other was centralized control over the entire Chinese heartland, which gave the dynasty the human and material resources necessary to carry out its policies.