The origin of the Xianbei-Tuoba people is described differently in the official histories of the Northern and Southern dynasties:the former holds that the Tuoba refers to the Xiongnu,while the latter regards them as originating from the Xianbei.The former argument states that the Tuoba derive from the offspring of a Xiongnu woman called"Tuoba"and Li Ling,a military officer of the Han dynasty who surrendered to the Xiongnu,an explanation that may be the result of the Xiongnu's having gained control over the northern part of Dai state when Fu Jian asked the Gudu,Tiefu and Helian tribes to govern the area separately after Dai's former ruler Shi Yijian was defeated by the Former Qin dynasty.Furthermore,the Xiongnu played an important role in Emperor Daowu's founding of the state,so that the"Xiongnu legend"remained in parallel with the"Xianbei story"for a long time within the Tuoba.When Cui Hao was put in charge of compiling the dynastic history,he reclaimed the "Xiongnu legend"in order to cater to the Xiongnu Queen Helian and Emperor Taiwu.Although not included in The Record of the Kingdom(Guo Ji) due to the objection of the top officials of the Northern Wei dynasty,the"Xiongnu legend"spread to the Southern dynasty and was incorporated into the Song Annals(Song Shu).The change of names of the Northern tribes in middle antiquity was primarily driven by politics,complicated by multiple factors such as kinship,territory,and society.The way the "Xiongnu legend"was formed and circulated may be a case in point.