Hồ Quý Ly
In 1387, Nghệ Tông appointed Hồ Quý Ly as Co-Prime Minister ("Đồng bình chương sự"), giving him as much power as Nghệ Tông's eldest son, Prime Minister Trần Ngạc (Prince Trang Định). Facing this threat, Emperor Phế Đế allied with Trần Ngạc to overthrow Hồ Quý Ly. However, Quý Ly had already got ahead of this plot by a defamation campaign against the Emperor which ultimately made Nghệ Tông decide to dethrone Phế Đế in December 1388. Phế Đế was downgraded to Prince Linh Đức and forced to commit suicide while his supporters in royal court were swept by Hồ Quý Ly's side. From now on it was Hồ Quý Ly who held the highest position and power in royal court.