燕王
Eventually, he gained the confidence and trust of the prince. Ma was also known as "Sanbao" during his service in the household of the Prince of Yan. This name was a reference to the Buddhist Three Jewels (, also known as triratna). This name could also be written , literally "Three Protections." Ma received a proper education at Beiping, which he would not have had if he had been placed in the imperial capital, Nanjing, as the Hongwu Emperor did not trust eunuchs and believed that it was better to keep them illiterate. The Hongwu Emperor purged and exterminated many of the original Ming leadership and gave his enfeoffed sons more military authority, especially those in the north, like the Prince of Yan.