How can it be called annexation? This place has long been ours, but it disappeared after the Five Dynasties and Ten Kingdoms. Later, it was briefly recovered, and soon it fell, and finally it became a vassal state.

In 2 14 BC, the Qin dynasty briefly unified Lingnan area and established Nanhai, Guilin and Xiangsan counties. Including northern Vietnam. Later, with the demise of the Qin Dynasty, Zhao Tuo took the opportunity to stand on its own two feet and established Nanyue State.

In BC 1 1 1 year, South Vietnam was destroyed by the Han Dynasty, and nine counties were established, namely Nanhai, Cangwu, Yulin, Hepu, Jiaozhi, Jiuzhen, Rinan, Zhu Ya and Daner, among which Jiaozhi, Jiuzhen and Rinan were mainly located in today's Vietnam. Since then, northern and central Vietnam have been ruled by the Central Plains Dynasty for thousands of years.

At the end of the Tang Dynasty, he crossed his toes and took advantage of the chaos in the Central Plains to stand on his own feet. The nearest Nanhan regime is weak and unable to recover. After the establishment of the Northern Song Dynasty, the best chance to recover Jiaodi was when Pan Mei destroyed the Southern Han Dynasty, which was the rebellion of the twelve Jiaodi generals at that time. As long as Pan Mei sent troops south, it would be easier to recover Vietnam.

Unfortunately, the Qidan in the north put too much pressure on the Song Dynasty. In order to cope with the invasion of the Khitans, Pan Mei immediately sent troops to the north after destroying the Southern Han Dynasty, and the excellent opportunity to recover this place was missed.

In the Yuan Dynasty, it was really not easy to destroy Yue. At that time, Vietnamese talents came forth in large numbers, and the monarch and the minister were United and United. The Yuan Army launched three large-scale wars, even hitting central Vietnam, but ultimately failed to gain a foothold in the local area and was forced to retreat, with considerable losses.

After the establishment of the Ming Dynasty, during the ruling period, the Chen Dynasty of the State of Yue was usurped by Hu, and the legacy of the Chen Dynasty came to the Ming Dynasty, demanding that the Ming Dynasty send troops to annihilate the rebels and re-establish the descendants of Chen. Later, the Ming army went south, destroyed Hu, and ruled Vietnam directly on the grounds that the descendants of Chen Dynasty were killed by Hu. Twenty years later, local uprisings broke out one after another, and the Ming Dynasty was unable to govern, so Ming Xuanzong decided to give up.

In the Qing Dynasty, the three emperors of Kang Yong focused on the northwest. They fought in the northwest all the year round and paid little attention to the south. They didn't have the energy to win Vietnam, so they just took it as a tribute.