During the Three Kingdoms period of ancient China, there was constant warfare occurring in the Central Plain of China. Northerners began to enter into Fujian region, causing the region to incorporate parts of northern Chinese dialects. However, the massive migration of northern Han Chinese into Fujian region mainly occurred after the Disaster of Yongjia. The Jìn court fled from the north to the south, causing large numbers of northern Han Chinese to move into Fujian region. They brought the old Chinese — spoken in Central Plain of China from prehistoric era to 3rd century — into Fujian. This then gradually evolved into the Quanzhou dialect.
What happened when the Jin court began to enter the Fujian region?