Lang Son Vuong Le Nghi Dan was Emperor Le Nhan Tong's half brother. Nghi Dan and Phan Ban, Pham Don plotted to assassinate the Emperor. In 1459, they climbed over the citadel wall at midnight to kill Emperor Nhan Tong and the king's mother. Nghi Dan set himself upon the throne as Emperor Le Nghi Dan. The insane monarch killed many court dignitaries to spread discontent around. Eight months later, the high officers plotted to kill Phan Ban, Pham Don, then ordered to close all the gates of the capital and to search for Nghi Dan. The monarch was put to death. The officers enthroned Prince Tu Thanh as Emperor Le Thanh Tong. Historians never mentioned about the coin of Thien Hung thong bao, but coins were found in Viet Nam.