Lan Yu ( general ) Lan Yu ( died 1393 ) was a Chinese general who contributed to the founding of the Ming Dynasty . He is counted among the 10 Muslim Defenders of the Ming ( ) . His ancestral home was in present - day Dingyuan County , Anhui . In 1393 Lan was suspected and accused of plotting a rebellion and eventually put to death by the Hongwu Emperor . About 15 , 000 people were implicated in the case and executed . Biography . According to the " History of Ming " , in his early years , Lan Yu was a subordinate of Chang Yuchun , another Muslim 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 Yan 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 . In 1381 , Lan Yu was appointed " Left Deputy General Who Conquers the South " ( ) and accompanied Fu Youde to attack Yunnan and pacify the region . He was rewarded with 500 " dan " of grain and his daughter was granted the title of " Princess Consort of Shu " ( ) . In 1387 , Nahachu ( ) of the Northern Yuan invaded Liaodong and the Hongwu Emperor sent Feng Sheng , with Lan Yu and Fu Youde as his right and left deputies respectively , along with a 200 , 000 - man army to attack him . Nahachu was defeated and surrendered . Lan Yu garrisoned the army at Jizhou ( ) . In 1388 , the Hongwu Emperor commissioned Lan Yu as General - in - Chief ( ) and sent him with 150 , 000 troops to attack the Northern Yuan ruler Uskhal Khan . In the fourth lunar month of that year , Lan Yu ' s force arrived at Buir Lake and defeated the Northern Yuan army , capturing Uskhal Khan ' s family members numbering more than 100 , more than 77 , 000 civilians , more than 150 , 000 livestock , along with several priced items , including Uskhal Khan ' s imperial seals . Uskhal Khan attempted to flee to the Mongol Empire ' s old capital of Karakorum , but was killed shortly after the defeat . The Hongwu Emperor was pleased when he received news of Lan Yu ' s victory and intended to grant Lan the title of " Duke of Liang " ( 梁國公 ) , but changed the Chinese character for " Liang " from " 梁 " to " 涼 " after he heard that Lan seized a Mongol noble lady for himself and violated her . This resulted in a change in the area that was to be Lan Yu ' s dukedom . Despite so , Hongwu still praised Lan Yu as " comparable to Wei Qing of the Han Dynasty and Li Jing of the Tang Dynasty " . In 1392 a surrendered Yuan general Yuelutiemu ' er ( 月魯帖木兒 ) rebelled in Jianchang ( present - day Jianchang County , Liaoning ) and Lan Yu was sent to suppress the revolt . Lan Yu crushed the uprising and captured Yuelutiemu ' er and his son , and was appointed as the Crown Prince ' s Tutor ( 太子太傅 ) for his achievement . As he made more achievements , Lan Yu became more arrogant , self - indulgent and unbridled . He started abusing his power and status and behaved violently and recklessly , sometimes even showing disrespect towards the emperor . Once , after he seized land from peasants in Dongchang ( 東昌 ) , an official questioned him on his actions , but Lan Yu drove the official away in anger . In another incident , after Lan Yu returned from a campaign in the north , he arrived at Xifeng Pass ( 喜峰關 ) , where the guards denied him entry as it was already late at night , but Lan led his men to force his way through . When he was away at war , Lan Yu sometimes also demoted officers at his own will and defied orders , to the extent of going to battle without permission . During his appointment as the Crown Prince ' s Tutor , Lan Yu was unhappy that his post was lower than the dukes of Song and Ying , so he exclaimed , " Am I not fit to be the Imperial Tutor ( 太師 ) ? " The Hongwu Emperor became more angry with Lan Yu after learning of these incidents . Lan Yu had a close friendship with the crown prince Zhu Biao . Once after Lan Yu returned from a campaign against the Mongols , he warned the crown prince that Zhu Di ( the Prince of Yan and future Yongle Emperor ) seemed to be a likely a threat to his succession . Zhu Di heard about this , so after Zhu Biao died in 1392 , he cautioned the Hongwu Emperor that Lan Yu and other founding pioneers of the dynasty were becoming a threat to the throne and should be dealt with before they get out of control . Lan Yu and others did not restrain themselves and continued behaving in the same manner as they did . Around this time , Hongwu was already making plans to eliminate them . Five months later when Hongwu appointed Zhu Biao ' s son Zhu Yunwen ( future Jianwen Emperor ) as the new crown prince , he allowed Lan Yu to continue serving as the Crown Prince ' s Tutor . Death . In the second lunar month of 1393 , a Jinyiwei ( secret police ) commander Jiang Huan ( 蔣瓛 ) accused Lan Yu of plotting a rebellion and a search was conducted in Lan ' s residence and around 10 , 000 Japanese sword s were found . The Hongwu Emperor immediately had Lan Yu put to death on a charge of treason . Lan Yu ' s clan was exterminated to the third degree and his properties confiscated . More than 15 , 000 people were implicated and executed in this incident , including 12 marquises and two counts . This incident is known historically as the Lan Yu Case ( 藍玉案 ) . It was believed that Hongwu Emperor orchestrated his death to eliminate any threat for his successor Zhu Yunwen ; ironically , Lan Yu ' s death contribute greatly to Zhu Yunwen ' s downfall as after his death , there were no capable generals that could prevent the powerful Zhu Di ( future Yongle Emperor ) from usurping the throne after Hongwu Emperor ' s death .