Analysis of information sources in references of the Wikipedia article "Sui dynasty" in English language version.
Yang Jian (r. 581–604), the founder of the Sui dynasty, was a member of the ethnically mixed, militaristic northwestern Chinese aristocracy developed during the period of division. The Yang clan had served, and intermarried with the Xianbei for generations. (...) Although he was a product of the mixed-ethnicity northern aristocracy, Yang Jian made a point of emphasizing Han Chinese cultural identity.