Yong-le: Year 13, Month 8, Day 22
24 Sep 1415
In Jiao-zhi, the administration of Xin-an Prefecture was moved to within the walls of Zhen-yi Guard and both Nan-ce Subprefecture and Zhi-ling County were placed under its jurisdiction. Also, the two counties of Duo-yi and Tai-ping were placed under the jurisdiction of Zhen-man Prefecture. Previously, Nan-ce and Zhi-ling were under the jurisdiction of Liang River and Duo-yi and Tai-ping were under the jurisdiction of Xin-an. At this time, the Jiao-zhi Provincial Administration Commission advised: "Nan-ce and Zhi-ling are near Xin-an, while Duo-yi and Tai-ping are near Zhen-man. A change in the jurisdiction would facilitate administration. Also, Zhen-yi Guard is in the area of Nan-ce and Zhi-ling. It would be convenient to move the administration of Xin-an Prefecture within the walls of the Zhen-yi Guard." The Emperor approved all these proposals.
Zhong-yang Yan-jiu yuan Ming Shi-lu, volume 13, page 1865