In 222 BC, after Qin Shi Huang unified the six kingdoms, he sent Tu Sui to lead 500,000 Qin troops to attack Lingnan "to conquer the king of Baiyue in the south". In 214 BC, the Qin army basically occupied Lingnan. Then, Qin Shi Huang established three counties in the captured Lingnan area, namely "Guilin, Xiang, and Nanhai". He included the Hong Kong area into his territory and placed it under the jurisdiction of Panyu County. From then on, Hong Kong was placed under the jurisdiction of the central government and clearly became the territory of the Central Plains Dynasty at that time. From then until the Qing Dynasty, as the Central Plains civilization migrated southward, the Hong Kong area gradually developed.