While Lê Văn Hưu set the starting point for the history of Vietnam by the foundation of the Kingdom of Nam Việt, Ngô Sĩ Liên took a further step by identifying the mythical and historical figures Kinh Dương Vương and his son Lạc Long Quân as the progenitor of the Vietnamese people. Because of the lack of historical resources about Kinh Dương Vương and Lạc Long Quân, some suggests that Ngô Sĩ Liên's explanation of the Vietnamese people's origin was a measure to extend the longevity of the Vietnamese civilization rather than a literal point of departure. From the very beginning of his work, Ngô Sĩ Liên had another difference to Trần scholars in regard to the Hồng Bàng Dynasty, that was while the Trần Dynasty scholars only mentioned the Hồng Bàng Dynasty as a symbol of excellence in the history of Vietnam, Ngô Sĩ Liên defined it the first Vietnamese dynasty which reigned the country from 2879 BC to 258 BC and thus predated the Xia Dynasty, the first dynasty of China, for more than 600 years. However, Ngô Sĩ Liên's account for that long period was so brief that several modern historians challenged the authenticity of his chronology for the Hùng Vương, kings of the Hồng Bàng Dynasty, and speculated that Ngô Sĩ Liên created this specific chronology mainly for the political purpose of the Lê Dynasty.