宋代曾公亮在《武经总要》中提到中国为加强南海海防，设立巡海水师，巡视南海。
It is mentioned in Zeng Gongliang 's Wujing Zongyao ( Outline Record of Military Affairs ) that , in order to strengthen defense in the South China Sea , China established naval units to conduct patrols therein .
武经总要