Keen to exploit the French presence in east Asia, he grabbed a naval base in China, then sent a flotilla to attack Annam (Vietnam) where Catholic missionaries had provoked a backlash, with the emperor Tu Duc trying to reject Catholic infiltration by executing two Spanish priests. In September 1857, French troops seized Da Nang and Saigon; both were repelled by the Vietnamese, but Napoleon dispatched reinforcements that in June 1862 retook Saigon. Thus was established the French colony of Cochinchina.
