Under Emperor Napoleon III (1808-73), France wanted to contain Siamese (Thai) expansionism in Indochina (Vietnam, Cambodia, Loas), to gain a larger share of overseas markets there, and to end the Vietnamese persecution of French Christian missionaries. Continued Vietnamese hostility to westerners led to a joint French and Spanish expedition's bombardment and seizure of the port city of Tourane (Da Nang, Vietnam) in the late summer of 1858. Faced with problems from tropical disease and food shortages, the expedition decided not to move against the Vietnamese capital of Hue to the north, but instead sailed south to Saigon (Ho Chi Minh City) in Cochin China (south Vietnam). Saigon was seized in 1859, and a 1,000-man Franco-Spanish garrison was left there while forces returned to tourane to meet renewed threats. With its troops ravaged by cholera and engaged also in a war in China, France tried unsuccessfully to negotiate a peace with Vietnamese king Tu Duc (1829-83). The Franco-Spanish garrison at Saigon withstood a nearly yearlong Vietnamese siege until a French force arrived to relieve it in February 1861. French troops, freed from duty in China, moved into the three eastern provinces of Cochin China provinces. Faced with an insurrection in Tonkin (north Vietnam), Tu Duc sued for peace (1862); he ceded to the French the three eastern Chochin China provinces (Saigon, My Tho, Bien Hoa) and the Poulo Condore (Con Son) islands and agreed to open three ports to French trade, to allow religious freedom, and to pay a large indemnity. Under French military pressure, Tu Doc ratified the peace treaty in April 1863. That same year Cambodia's King Norodom (1834-1904) accepted a French protectorate over his country. In 1867, Siam gave up its claims in Cambodia to the French.