Yao Xing in the context of "Qiao Zong"

Qin, known in historiography as the Later Qin (simplified Chinese: 后秦; traditional Chinese: 後秦; pinyin: Hòuqín; 384–417) or Yao Qin (姚秦), was a dynastic state of China ruled by the Yao clan of Qiang ethnicity during the Sixteen Kingdoms period in northern China. As the only Qiang-led state among the Sixteen Kingdoms, it was most known for its propagation of Buddhism under its second ruler, Yao Xing, who sponsored the Madhyamakin monk, Kumārajīva to translate Sanskrit Buddhist text into Chinese.

All rulers of the Later Qin declared themselves emperors, but for a substantial part of Yao Xing's reign, he used the title Heavenly King. Historiographers gave the state the prefix of "Later" to distinguish it with the Former Qin and Western Qin as it was founded during the Former Qin's collapse after the Battle of Fei River and went on to conquer the Former Qin's power base in the Guanzhong. With Chang'an as its capital, the Later Qin also controlled Henan and vassalised the Western Qin, the four Liangs (Later, Southern, Northern and Western), Southern Yan, Qiao Shu, Chouchi and various tribes of the Ordos region.

Helian Bobo (Chinese: 赫連勃勃; Middle Chinese Guangyun: [xɐk-li̯ɛn˩ bʰuət-bʰuət]; 381 – c. September 425), né Liu Bobo (劉勃勃), with the epithet Qujie (屈孑), was the founder of the Xiongnu state of Xia, which rose to prominence during the Sixteen Kingdoms period. He belonged to the Tiefu (鐵弗) branch of the Xiongnu, was a descendant of the southern chanyu Liu Qubei, and the son of Liu Weichen, its chieftain. After his father was killed by Northern Wei and the tribe collapsed, Liu Bobo sought refuge with Moyigan, a Xianbei chieftain of Later Qin, and married Moyigan's daughter. As an adult, noted for his imposing stature, eloquence, and intelligence, he won the favor of Emperor Yao Xing of Later Qin, who appointed him a general and placed more than thirty thousand men from the Tiefu and other tribes under his command.

In 407, after Later Qin made peace with Northern Wei, Liu Bobo rebelled. Claiming descent from the Xia dynasty royal line, he styled himself Heavenly King of Great Xia and Grand Chanyu and adopted the era name Longsheng (龍昇), marking the establishment of the Xia state. He spent the following years roaming the northern steppe, deploying cavalry offensives against Later Qin and Southern Liang in the Shuofang region.