一、明代北京长城沿线军镇与穵运自明成祖迁都北京,京师防卫成为国家头等大事,为了备御蒙古,明王朝在北部边境地带的战略要地和交通要冲都修建了城堡,东从山海关起,西至嘉峪关,修筑了长城,称为边墙,其中宣化、大同之南还修筑了内长城,称为次边,这就是今日见到的万里长城。明王朝在长城沿线设置军事重镇,派驻重兵。自明初至中叶,明朝先后设置了九个重镇统领前线军士,统称九边镇。“初设辽东、宣府、大同、延绥四镇,继设宁夏、甘肃、蓟州三 First, the Ming Dynasty along the Great Wall along the Beijing Military Region and the Qing Yuncheng since the ancestral home in Beijing, capital defense became the country’s top priority, in order to prepare for Mongolia, the Ming Dynasty in the northern border strategic sites and traffic hub are built castle east from the Shanhaiguan , West of Jiayuguan, built the Great Wall, known as the side walls, including Xuanhua, Datong South also built the Great Wall, known as the second, this is today to see the Great Wall. The Ming dynasty set a military center along the Great Wall and was heavily armed. Since the early Ming to the mid-Ming Dynasty, the Ming Dynasty has set up nine major front-line sergeant command center, collectively known as nine side town. ”Set up Liaodong, Xuanfu, Datong, Yan Sui four towns, followed by Ningxia, Gansu, Jizhou three