What wars caused northerners to move south in Tang and Song Dynasties? Please be more specific. Good answer. I'll get extra points.

The "An Shi Rebellion" in Sui and Tang Dynasties had great political energy, but their actions in population migration were far less than those in Qin and Han Dynasties. The reason is that people have experienced centuries of turmoil before this, suffering from displacement and moving to other places, and they are very disgusted with population migration psychologically. In addition, the official immigrants in Qin and Han dynasties, including stationing troops to defend the border, mostly failed to fulfill their responsibilities, often harming first and not benefiting, and learned a lot. Therefore, the official population migration in Sui and Tang Dynasties was very few. It was not until the "An Shi Rebellion" that shocked the whole country broke out that the Yellow River basin fell into a sea of blood again, which triggered another tide of population migration to the south. According to historical records: "In the last years of Tianbao, An Lushan rebelled, the son of heaven went to Shu, the toast ran south, and there were a sea of people in Wu." "The world is dressed in clothes, avoiding Wu Dong, and Yongjia moving south is not here." The aftermath of this migration tide continued until the end of the Tang Dynasty, the Five Dynasties and the Ten Kingdoms period. At this point, the population size in southern China has reached the same level as that in the north for the first time.

From the "difficulty of Jingkang" to the "difficulty of Jingkang" caused by the massive invasion of Jin people to the south at the end of the Southern Song Dynasty, and then to the confrontation between Song and Jin 100 years, China suffered huge social unrest again, resulting in population migration, which was large in scale and long in duration, and its nature and form were comparable to "Yong Jia's funeral" and "An Shi's rebellion". According to the record: "At the end of the warning, all the scholars avoided the ground ... those who were wearing clothes rushed to the road." "Northwest scholar-officials suffer from Jingkang and live in Wuling". "People from all directions gathered in Zhejiang, which is a hundred times as usual." Even some remote mountainous areas in the south have accepted many immigrants. For example, in Rongxian County, Guangxi, "since Guangxi and Guangzhou were introduced to cross the river, many people have stayed at home." The migration of a large number of people from the north to the south has greatly promoted the social development in the south. Many civil military commanders in the Southern Song Dynasty also came from the north, including Yue Fei, Han Shizhong, Zhang Jun, etc. Among the civilians, there were also many celebrities who went south, such as Li Qingzhao and Xin Qiji.