The abdication of Bảo Đại (Vietnamese: Chiếu thoái vị của Hoàng Đế Bảo Đại) took place on 25 August 1945 and marked the end of the 143-year reign of the Nguyễn dynasty over Vietnam ending the Vietnamese monarchy. The fall of the Nguyễn dynasty also led to the fall of its Empire of Vietnam de facto controlled by Japan. Emperor Bảo Đại abdicated in response to the August Revolution. A ceremony was held handing power over to the newly established Democratic Republic of Vietnam, which was established during the end of World War II in Asia as Vietnam had been occupied by French and later Japanese imperialists.
After the Việt Minh sent a telegram to the Imperial City of Huế demanding the abdication of Emperor Bảo Đại, he announced that he would abdicate and officially abdicated on 25 August. After a representative of the Việt Minh convinced Bảo Đại to hold a public abdication ceremony, he did so on 30 August 1945. The passing of the ceremonial seal and sword had been seen as symbolically "passing the Mandate of Heaven over to the government of the Democratic Republic of Vietnam". Following his abdication Emperor Bảo Đại became "citizen Vĩnh Thụy" (公民永瑞, công dân Vĩnh Thụy) and would become an advisor to the new Democratic Republic of Vietnam government in Hanoi.
After the French returned following the defeat of the Axis powers (Germany, Japan, etc) they attempted to re-install Bảo Đại back on the throne and created the State of Vietnam with him as its "Chief of State" or "Chancellor" (國長, Quốc trưởng), the French also oversaw the creation of the Domain of the Crown where he was still officially considered to be the Emperor, this territory existed until 1955.

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