In the years 1856–60, Great Britain, France and China were involved in a war, which has been referred to by different names, depending, naturally enough, on the nationality of the historian. Scholars in China, almost without exception, call it the Second Opium War. Historians in England, however, usually prefer to call it the Second Anglo-Chinese War or even the Second China-foreign War. It has been given yet another name, the Arrow War. None of these names is, strictly speaking, entirely appropriate. To begin with, the war was not fought over the question of opium, although in many ways it was a continuation of the Opium War of less than two decades before. In the last analysis, it was a consequence of an ever-expanding British economy. Secondly, although it is true that Great Britain and China were the chiefcontenders, the title Anglo-Chinese War ignores the part played by France in the campaign. Then the name Second China-foreign War, apart from betraying the English desire to forget that part of their past, is misleading because it focuses attention on China herself rather than on British encroachment on that country. Finally, the Arrow incident was, like the burning of opium by Commissioner Lin, an immediate cause of the quarrel; but once London had decided to resort to arms, little further reference was made to it in British diplomatic documents. The name Arrow War is particularly irrelevant for the period after the scene of confrontation had changed from Canton to Tientsin and then Peking. On balance, however, the names Second Anglo-Chinese War and Arrow War seem preferable because they do not carry overtones of nationalist prejudice. The latter title has the additional merit of illustrating how, in the age of European expansion, a small diplomatic incident could be magnified to justify the use of force to press home demands unrelated to it. It reflects the fact that the receiving end—in this case China, and in particular her Imperial Commissioner for Foreign Affairs, Yeh Ming-ch'en—tried throughout to argue the case over the specific casus belli, whereas for the British the whole affair was merely a pretext for wider demands to be made on China. Thus it seems more appropriate to call the conflict the Arrow War; and in order to examine its origins, the first step will be to analyse the documentary evidence related to the Arrow incident. Some papers in the Chinese language have only recently been made available to scholars in the Public Record Office. London, and these provide additional information for a re-investigation of the origins of the war.