Vietnamese police have detained a man who broke into a history exhibit and damaged an antique throne considered to be one of the nation’s most precious artefacts, conservation officials said on Sunday.The ornate red-and-gold Nguyen dynasty throne was the royal seat of the last feudal family to rule Vietnam between 1802 and 1945 and has been preserved for posterity in Hue city’s Thai Hoa Palace.A 42-year-old man “snuck into the Nguyen dynasty display area, screamed and then broke the front left armrest” around midday on Saturday, a statement from the Hue Monuments Conservation Centre (HMCC) said.In footage circulating on social media and Vietnam news sites purporting to show the incident, the man can be seen sitting cross-legged on the two-century-old throne that is adorned with dragon motifs.He was quickly arrested but showed “signs of psychosis, screaming, talking nonsense and could not answer the investigator’s questions”, the HMCC said.Police detained him to conduct a psychiatric assessment, it said, while the throne will be removed for repair and preservation efforts.“This is an extremely rare incident,” the HMCC statement said.Vietnam’s ministry of culture, sports and tourism has asked for an urgent report on the incident.The central city of Hue was established as the capital of unified Vietnam under the Nguyen dynasty.It was recognised as a world heritage site by Unesco in 1993 and hosts several ancient palaces, tombs and artefacts.