Putian. According to the genealogy of Chua's Ancestral Hall in Longtian Township, Chenghai, all the people in Longtian Township moved from Putian. According to legend, Longtian Township was built in the year of Song San (1043) and named as "Tianliao". During the Chongzhen period of the Ming Dynasty, Lu Sheng, who was single in the village, changed her name to Longtian according to the meaning of "seeing dragons in the fields". During the reign of Zhao Xiaoyun, the founding emperor of the Southern Song Dynasty, Sun Caiqiao, the fifth generation of Cai Xiang, Putian County, Fujian Province, moved here about 125S. It has been nearly 750 years since then, and his descendants have thrived and become one of the prosperous families in Chenghai County. With the changes of history, the Cai family in Longtian Township has flourished from less to more and from weak to strong in the long-term struggle for survival and development and the arduous struggle against natural and man-made disasters. Chenghai County was established in the forty-second year of Jiajing in Ming Dynasty (1563) for the ethos of Jinghai, but the ethos of the sea flourished for a long time. In the first year of Emperor Kangxi of Qing Dynasty, the people were forced to move 50 miles inward. In 35 years, the people moved inward one after another, and the county administration was abolished. Government agencies and people's homes were completely destroyed, people were displaced, and a large number of people died, which was terrible and terrible. There is no reason for this. Genealogy records that the descendants of Cai family were exiled, displaced, fighting for survival, leaving their homes to fight for money, and it was not until the eighth year of Kangxi that they returned to the county seat to let the people rebuild their homes. During this period, historical materials were lost. This genealogy was compiled by Yang Gong in the 12th Qianlong Dynasty after he spent more than 60 years in Fuxian County, leaving precious literature and history materials for later generations.