雁门关
According to the "History of Ming", in his early years, a Muslim general Lan Yu was a subordinate of Chang Yuchun, another general under the rebel leader Zhu Yuanzhang (later the Hongwu Emperor of the Ming). Lan Yu was also the younger brother of Chang Yuchun's wife. As Lan Yu displayed courage in battle, Chang Yuchun spoke well of him numerous times in front of Zhu Yuanzhang and Lan was later promoted from "guanjun zhenfu" () to an administrative officer in the commander-in-chief's office (). In 1371, Lan Yu followed Fu Youde to attack Shu (covering present-day Sichuan) and conquered Mianzhou () around present-day Mianyang. In 1372, he accompanied Xu Da on a campaign against the Northern Yuan Dynasty in Mongolia, departing from Yanmen Pass and defeating the Yuan armies at Mount Luan () and near the Tula River (). Seven years later he followed Mu Ying to attack Tibet, capturing three tribal leaders and around a thousand men. For his efforts, in 1379, Lan Yu was conferred the title of "Marquis of Yongchang" (), in addition to receiving 2500 "dan" () of grain and a "shiquan" (), a type of plaque granted by the emperor to officials in recognition of their contributions.