The splitting of the Toba empire into these two separate realms was the result of the policy embarked on at the foundation of the empire. Once the tribal chieftains and nobles had been separated from their tribes and organized militarily, it was inevitable that the two elements should have different social destinies. The nobles could not hold their own against the Chinese; if they were not actually eliminated in one way or another, they disappeared into Chinese families. The rest, the people of the tribe, became destitute and were driven to revolt. The northern peoples had been unable to perpetuate either their tribal or their military organization, and the Toba had been equally unsuccessful in their attempt to perpetuate the two forms of organization alongside each other. These social processes are of particular importance because the ethnical disappearance of the northern peoples in China had nothing to do with any racial inferiority or with any particular power of assimilation; it was a natural process resulting from the different economic, social, and cultural organizations of the northern peoples and the Chinese. 2 _Appearance of the (Gök) Turks_ The Toba had liberated themselves early in the fifth century from the Juan-juan peril. None of the fighting that followed was of any great importance. The Toba resorted to the old means of defence against nomads--they built great walls. Apart from that, after their move southward to Loyang, their new capital, they were no longer greatly interested in their northern territories. When the Toba empire split into the Ch'i and the Northern Chou, the remaining Juan-juan entered into treaties first with one realm and then with the other: each realm wanted to secure the help of the Juan-juan against the other.