What dialect was used in Ningzhen area before Yongjia funeral?

During the Yongjia Rebellion at the end of the Western Jin Dynasty, there were more than 900,000 northern immigrants from Du Nan, Guan Yi, and the northern dialect brought by the immigrants extended to the west of Maoshan. Wang Dao, the prime minister of the Eastern Jin Dynasty at that time, in order to contact the gentry in the south of Ningzhen, said that Wang Dao was nothing but Wu dialect, and was laughed at by the gentry in the north. From this historical record, it can be proved that Ningzhen area was a Wu dialect area before the Yongjia Rebellion in the Western Jin Dynasty, including the early years of the Eastern Jin Dynasty.