As far as Later-Goguryeo and Gungye are concerned, there is no literature data beyond the scope of information in Samguk-sagi. The biography of Gungye goes beyond a personal biography and is also the history of the Later-Goguryeo dynasty. Therefore, anyone interested in the history of Gungye and Later-Goguryeo analyzes the records of Gungye’s Biography and restores their history by giving meaning to them. If so, the family and birth-related records at the beginning of Gungye’s Biography are also a kind of gateway to the restoration of Later-Goguryeo history.
First, previous studies that have accessed this information were checked. As a result, it was confirmed that there were two trends. One view was to solve a problem within the range of information conveyed by the historical material, and the other was to find a solution outside the scope of the historical material. Under the great premise that Gungye is son of the Silla king, the former is view of choosing the father of Gung-ye among King Heonan or King Gyeongmun. The latter does not agree with the fact that Gungye is from the royal family of Silla, in connection with the integrity and artificiality of the subsequent birth-related records.
Leaving aside the controversial part, we first focused on the issue of ‘information itself’. It would have been difficult for the compilers of Samguk-sagi to identify either King Heonan or King Gyeongmun through the data they obtained. In the end, the conflicting family information of Gungye should be viewed as continuing to the Samguk-sagi without any confusion that occurred before the Samguk-sagi. In particular, the main focus of the evaluation of Gungye was on criticizing Gungye for betraying ‘own country’[宗國], Silla. Accordingly, I think the editors noted that Gungye was from the Silla’s royal family. Goryeo was founded after overthrowing Later-Goguryeo and Wanggeon was a servant of Gungye, so there were some flaws in the legitimacy of establishing the government. Therefore, rather than clarifying the historical facts of the previous dynasty, Therefore, rather than clarifying the historical facts of the previous dynasty, the focus was on emphasizing the reason why Gungye should be expelled, so it was considered that the information that was involved in the Samguk-Sagi continued without any inspection. In other words, there was no special opportunity to resolve Gungye’s family problem.
Next, attention was paid to ‘White Rainbow’[白虹] as a natural phenomenon contained in the birth-related information. As a result, we found out that the old notion that the appearance of a ‘白虹’ symbolized an ‘ominous sign’[咎徵] was also widely known to Silla, who enjoyed the 9th and 10th centuries. It is currently not possible to determine whether that natural phenomenon on the day Gungye was born is fiction. However, I would like to suggest that it is necessary to pay attention to the way of thinking at the time, the process of forming information, and the internal logic, which has been calling for the need to eliminate Gungye by mobilizing the ‘white rainbow’ as an ‘ominous sign’ since ancient times. In this context, it is regarded as a historical fact that Gungye was the prince of Silla.