Đồng Cổ - Temple connected with the “Oath-taking ceremony” in feudal times

The temple was once on Đồng Cổ Mountain in Đan Nê Commune, Yên Định District of Thanh Hóa Province. In the past, when King Lý Thái Tổ (1010–1028) fought in the war against Chiêm Thành (Champa), he once stayed in Trường An and dreamt of a man who wore velvet robes and told him, “I am the god of Đồng Cổ Mountain. I know that the King goes to conquer the southern enemies and I wish to stand by his side to help him.” After gaining the victory, the King went back to his homeland and ordered a temple built to the left of the eastern citadel to honor the god of Đồng Cổ Mountain. When King Lý Thái Tổ died, King Thái Tông (1028–1054) succeeded to the throne but before he became King, he also dreamt of the god who told him the king’s brothers, Dực Thánh Vương, Đông Chinh Vương and Vũ Đức Vương were hatching a plot to betray him. The three princes planned to ambush Thái Tông inside the citadel the following morning however, because of the god’s warning and with the help from his commanders, the crown prince was able to put down the revolt. After ascending the throne, King Lý Thái Tông ordered another temple built for Đồng Cổ on the right side of the royal citadel and chose the 25^th day of the 3rd lunar month to hold an “Oath-swearing” ceremony there. The King ordered his workers to build a tall altar erected with many flying flags in front of the citadel and ordered all his people to attend. The Đồng Cổ god’s worshipping tablet was placed in the middle of the altar. All the military and civilian mandarins from the eastern part of the country came into the temple, knelt and swore, “If as children we are undutiful towards our parents and if as subjects, we are unfaithful or disloyal to the King, we will be surely killed by the God". Later, the date of the ceremony was changed to the 4^th day of the fourth lunar month and was held annually through the Trần (13^th and 14^th centuries) and Lê (15^th century) dynasties. It was developed into a festival later.

Đồng Cổ Festival, connected with the bronze drum, was a symbol of physical strength as well as the traditional and ancient spirit of Vietnam. The festival was a unique, consolidating the morale and traditions of our nation.