The Sino-French War (, , ), also known as the Tonkin War and Tonquin War, was a limited conflict fought from August 1884 to April 1885. There was no declaration of war. The Chinese armies performed better than its other nineteenth-century wars and the war ended with French retreat on land and the momentum in China's favor. However lack of foreign support, French naval supremacy, and northern threats posed by Russia and Japan forced China to enter negotiations. China ceded its sphere of influence in Tonkin (northern Vietnam) to France and recognized all the French treaties with Annam turning it into a French protectorate. The war strengthened the dominance of Empress Dowager Cixi over the Chinese government, but brought down the government of Prime Minister Jules Ferry in Paris. Both sides ratified the Treaty of Tientsin. According to Lloyd Eastman, "neither nation reaped diplomatic gains." Prelude French interest in northern Vietnam dated from the late 18th century, when the political Catholic priest Pigneau de Behaine recruited French volunteers to fight for Nguyễn Ánh and help begin the Nguyễn dynasty, in an attempt to gain privileges for France and for the Roman Catholic Church. France began its colonial campaign in 1858, annexing several southern provinces in 1862 to form the colony of Cochinchina. French explorers followed the course of the Red River through northern Vietnam to its source in Yunnan, arousing hopes for a profitable trade route with China that could bypass the treaty ports of the Chinese coastal provinces. The main obstacle to this idea, the Black Flag Army – a well-organized bandit force led by the formidable Liu Yongfu – was levying exorbitant "taxes" on Red River trade between Sơn Tây and Lào Cai on the Yunnan border. In 1873, a small French force commanded by Lieutenant de Vaisseau Francis Garnier, exceeding his instructions, attacked northern Vietnam. Following a series of French victories against the Vietnamese, the Vietnamese government called on Liu Yongfu's Black Flags, who defeated Garnier's force beneath the walls of Hanoi. Garnier was killed in this battle, and the French government later disavowed his expedition. Henri Rivière's expedition in Tonkin In 1881, French Commandant Henri Rivière was sent with a small military force to Hanoi to investigate Vietnamese complaints about the activities of French merchants. In defiance of the instructions of his superiors, Rivière stormed the citadel of Hanoi on 25 April 1882. Although Rivière subsequently