Honey, p. 43: "In 1840 he sent an embassy led by the mandarin Ton That Tuong to France offering the French the monopoly of European trade with Vietnam, in return for an undertaken to defend the country in the event of an attack."
Chapuis, The Last Emperors, p.5 Quote: Two years later, in 1847, Lefebvre was again captured when he returned to Vietnam. This time Cecille sent captain Lapierre to Da Nang. Whether Lapierre was aware or not that Lefebvre had already been freed and on his way back to Singapore, the French first dismantled masts of some Vietnamese ships. Later on April 14, 1847, in only one hour, the French sank the last five bronze-plated vessels in the bay of Da Nang.
Sondhaus, p.75: "Rear Admiral Courbet blockaded Huế in August 1883 and directed an assault on its citadel, forcing the capitulation of the emperor of Annam"
