Career
He was a supporter of the unsuccessful Cần Vương (Aid the King) Movement of 1885-1889 which sought to restore sovereign authority to the Nguyễn throne. He was one among several leading scholars in the movement including Phan Đình Phùng, Phan Chu Trinh, Phan Bội Châu, and Huỳnh Thúc Kháng.