‘The liberation of South America’, wrote Castlereagh in 1807, ‘must be accomplished through the wishes and exertions of the inhabitants; but the change can only be operated…under the protection and with the support of an auxiliary British force’. The argument, familiar in political debate, was rare in official policy. Britain, it is true, had long regarded Spanish America as a source of strength for her rivals and a potential market for her manufactures. After the Peace of 1783 interest became more intense as British observers, impressed by the vulnerability of empires, claimed to see signs of rapid decline in the empire of Spain. Intelligence reports on Spanish America accumulated in government departments; plans for British attacks flowed from official and private sources; and a section of merchant opinion increased its agitation for military intervention in the area. Yet, apart from the conquest of Trinidad in 1797 and the attempted conquest of the Río de la Plata in 1806–7, British policy towards Spanish America was diffident in its approach and vague in its intent. There were, indeed, compelling reasons why Spanish America should remain on the margin of British policy. Britain's existing European and imperial interests necessarily dominated her policy and absorbed her resources. Until 1806, moreover, existing channels of trade in Europe and the rest of the world were sufficient to take the bulk of British industrial production. And military resources were usually insufficient to release troops either from Europe or the West Indies for major operations in a new theatre of war.

The province of La Convención, department of Cuzco, in Peru became familiar to citizens of the outside world in the early 1960s, when it was the scene of the most important peasant movement of that period in Peru, and probably in the whole of South America. This might legitimately attract the attention of the social historian. At the same time La Convención is a special version of a more general phenomenon, which ought also to interest the economic historian. It is ‘frontier territory’ in the American sense of the word, i.e. it belongs to the large zone of undeveloped land on the eastern edge of the Andes (the western edge of the Amazon basin) which has come under settlement and cultivation in recent decades, mainly for the cultivation of cash crops for the world market, but also for other economic purposes. Along the Andean slopes there are a number of such regions, into which, in their different ways, landlords and entrepreneurs penetrate with estates and trade, peasants in search of land and freedom. Mostly they are Indian peasants from the highlands, and the socio-economic background of the sierra and altiplano determines to some extent the forms of the new economy which take shape on the semi-tropical and tropical eastern slopes. These vary considerably, as we can tell by the various available monographs.

Social scientists make a fundamental assumption about the nature of the relationship between theory and fact. For them, theories are seen, not as guides to individual behaviour, but as tools for the clinical investigation of social processes. The end of this search is a better theory. A theory has most chance of acceptance if it seems elegantly to order a very large number of hitherto unrelated facts.