In many respects 1750 was a rather unremarkable year for the viceroyalty of Peru. Indeed, the author of one chronological history of the country could find only two events worthy of mention in that year (apart from the births of, among others, José Baquíjano y Carrillo, Francisco de Miranda, Alejo Toribio Rodríguez de Mendoza, Hipólito Unanue Pabón, José Pastor de Larinaga, and James Monroe, the future president of the future United States of America): the discovery on the beach at Huacho by fishermen of a crucifix venerated as ‘La Cruz del Sr de Varas’, and the hanging and quartering of the leaders of an Indian revolt at Huarochirí. Although he was correct in drawing attention to the importance of the last event – which was driven by not only indigenous discontent but also the resentment of local mestizos at the attempts of crown officials to lower their status by classifying them as tributaries – a more perspicacious observer might also have commented upon the significance for Peru of the unsuccessful attempts of Spain and Portugal to settle their long-standing boundary disputes in South America. The Treaty of Madrid of 1750, which sought for the first time since the late-fifteenth century to define realistic boundaries between the American territories of the Iberian states, was of direct significance for Peru in legitimising Portuguese (and, hence Brazilian) possession of vast tracts of Amazonia that nominally belonged to Spain under the terms of the 1494 Treaty of Tordesillas; its indirect significance was even more substantial, first in setting in train the complex series of events that would lead in 1767 to the expulsion of the Society of Jesus from Peru (and, of course, other parts of Spanish America as well as Spain itself). More crucially still, because of their failure to resolve definitively territorial disputes in the Río de la Plata between the two powers, the negotiations of 1750 also led eventually to the separation of Upper Peru from the old viceroyalty in 1776 primarily in an attempt by the Spanish crown to guarantee the financial viability and, therefore, the defensive integrity against further Portuguese intrusions of the newly-established viceroyalty of the Río de la Plata.