Because of its importance to the defense of coastal cities Zhangzhou and Xiamen, and as a base for extending control over Taiwan and Penghu, the island was referred to in the Ming dynasty as "an impregnable fortress dominating the gateway to the seas."
金門之得名，始於明朝時因其地位內捍漳廈、外制台澎，有「固若金湯、雄鎮海門」之勢，因而名之「金門」。