The French move into what they came to call Indo-China began, as the Hong Kong Register was to put it, with motives hostile to British power. Pre-revolutionary France had indeed seen such a move as a means of contesting Britain's supremacy in Asia: placing themselves between the growing empire in India and the growing trade with China, the French could embarrass their European rivals. But establishing themselves in Vietnam was easier said than done. The limited help they were able to afford Gia-long reaped them no great reward, and his successor, Minh-mang, even turned against the Catholic missionaries whom he saw as sources of subversion of his Confucian-style reunification. Continued anti-Catholic activity on the part of his successor was to give Napoleon III an excuse to intervene in the 1850s. But by then, as the Register noted, the old rivalry with the British had died out. The British had sought to open up trade with Vietnam, but, both before and after their victory over neighbouring China, the Vietnamese had refused to accept a commercial treaty. The British thus did not oppose the more forceful attempt the French made to open up Vietnam. Their only concern was lest the French should trench upon the territory of Laos and Cambodia, and thus undermine the independence of Siam, which the British saw as an outwork of their empire in Burma and Malaya. There was indeed a crisis over Laos, and thus over Siam, in 1893, but the French and the British came to terms in 1896. Their agreement in Southeast Asia was consolidated by their agreement in Europe, which the apprehension of Germany promoted.