On August 9, 1884, French naval forces attacked and captured Keelung on the island of Formosa in response to Chinese involvement in the Tonkin Campaign and specifically the Bắc Lệ ambush. Shortly afterwards, the French Navy′s Far East Squadron under Rear Admiral Amédée Courbet, comprising the cruisers , , and along with a number of smaller vessels, was sent up the Min River to attack the arsenal at Foochow. As they travelled upriver, the Chinese declared war on the French, officially marking the start of the Sino-French War.