File:Bản tấu của Bộ Lễ ngày 10 tháng 5 năm Thành Thái thứ 6 (1894) về việc lập đàn và các nghi thức của lễ tế đàn Âm Hồn.jpg

English: On the 23rd day of the 5th lunar month every year, Huế people from the inner city to the countryside, from old imperial families to ordinary workers, make a tray of offerings to commemorate a traumatic event of their ancestors. Huế, the day the capital fell in 1885. This day is considered a common death anniversary of all Huế people.

The night of July 4, 1885, or the night of the 22nd and early morning of May 23, the year of the Rooster, took advantage of the fact that the Resident-Superioe of the French protectorate of Annam Champeaux held a banquet to welcome Governor-General of the French protectorates of Annam and Tonkin De Courcy to visit Huế, Tôn Thất Thuyết, one of the officials. The head of the warring faction of the Annam court (Triều đình An Nam) ordered an attack on the French protectorate authorities. However, the attack failed against the powerful French forces and was attacked by the French army again. In that chaotic battle many officials, soldiers and civilians in Hue were killed. That day became one of the bloodiest and most painful days in the history of Huế.

Nine years after the fall of Hue, in 1894, the Thành Thái Emperor set up an altar to worship the dead souls of those who died in that historical event. However, up to now, not many people, including the people from Huế, know the origin and rituals of this practice. Therefore, the Vietnamese National Archives introduced this text from the imperial records of Nguyễn Dynasty document of the 6th year of the reign of the Thành Thái Emperor, which records very specifically about the establishment of the harp and the rituals of the Ân Hồn altar ceremony in Huế. The text was directly penned by the Thành Thái Emperor with "Châu điểm".