Han bureaucrats while the Eastern regime was controlled by the traditional steppe tribes. Northern Qi (550–577) and Northern Zhou (557–581) Eventually, Gao Huan's son Gao Yang forced the Eastern Wei emperor to abdicate in favor of his claim to the throne, establishing the Northern Qi dynasty (551–577). Afterward, Yuwen Tai's son Yuwen Jue seized the throne of power from Emperor Gong of Western Wei, establishing the Northern Zhou dynasty (557–580). Like its predecessor the Western Wei, the Northern Zhou reacted against sinicization by reviving Xianbei warrior culture: reviving Xianbei tunics, trousers and boots, reversing the sinicized surnames into Xianbei names and even giving Han officers Xianbei surnames. The Northern Zhou dynasty was able to defeat and conquer Northern Qi in 577, reunifying the north. However, this success was short-lived, as the Northern Zhou was overthrown in 581 by Yang Jian, who became Emperor Wen of Sui. With greater military power and morale, along with convincing propaganda that the Chen dynasty ruler Chen Shubao was a decadent ruler who had lost the Mandate of Heaven, the Sui Dynasty was able to effectively conquer the south. After this conquest, the whole of China entered a new golden age of reunification under the centralization of the short-lived Sui dynasty and the succeeding Tang dynasty (618–907). The core elite of the Northern dynasties, mixed-culture, and mixed-ethnicity military clans, would later also form the founding elites of the Sui and Tang dynasties. Hence, they tended to have a flexible approach to steppe nomads, viewing them as possible partners rather than intrinsic enemies. Southern dynasties The Jin were succeeded by a series of short-lived dynasties: Liu Song (420–479), Southern Qi (479–502), Liang (502–557) and Chen (557–589). Because all of these dynasties had their capital at Jiankang except Liang, they are sometimes grouped together with Eastern Wu and Eastern Jin as the Six Dynasties. The rulers of these short-lived dynasties were generals who seized and then held power for several decades but were unable to securely pass power of rule onto their heirs to continue their dynasty successfully. Emperor Wu of Liang (502–549) was the most notable ruler of his age, being a patron of the arts and of Buddhism. After the failure of the Liu Song's efforts to form an alliance with the Rouran, Goguryeo, Tuyuhun and smaller local powers to defeat the Northern Wei, the North and South were forced into tacitly acknowledging their equal