How was the history of Chinese literature divided?

In the history of Chinese literature, ancient literature was usually divided into three stages: the Pre-Qin philosophers, the Qin and Han Dynasties, and the Wei, Jin, and Southern and Northern Dynasties. Each stage consisted of seven sections, and each section was usually divided according to a specific topic or event. To be specific, the period of the Pre-Qin philosophers included the Spring and Autumn Annals, the Warring States Period, Han Feizi, and the Lü's Spring and Autumn Annals. The Qin and Han Dynasties included works such as Records of the Historian, Han Shu, Han Shu of the Later Han Dynasty, and Records of the Three Kingdoms. During the Wei, Jin, Southern and Northern Dynasties, there were works such as Jin Shu, Southern and Northern Dynasties Shu, Song Shu, Qi Shu, Liang Shu, Wei Shu, Northern Qi Shu, and Northern Zhou Shu. The theme or event of each paragraph is usually different, so the division is based on these different topics or events. For example, in the Records of the Historian, Sima Qian divided the history of the Qin and Han Dynasties into several stages, such as the struggle for hegemony between the vassals, the war between Chu and Han, and the unification of the six countries. Each stage had different events and characters. In Han Shu, the political system of the Han Dynasty was divided into several stages, such as Wang Mang's usurpation of the throne, the turmoil at the end of the Han Dynasty, and the Three Kingdoms period. Each stage had different political events and cultural phenomena.