An account of how citizens of the Viceroyalty of Peru, along its Pacific coastline, defended themselves their properties, businesses, and the vital commercial links that delivered vast quantities of Peruvian silver via the Isthmus of Panama to the Iberian Peninsula, in support of Spain's imperial ambitions in Europe and worldwide. The cornerstone of this complex and costly network was maritime defence mainly performed by the *Armada del Mar del Sur*, consisting of warships built in the region, manned by diverse elements of the local population, but increasingly financed by private resources rather than by the Crown. This was increasingly supplemented by the development of fortifications on shore in strategic locations such as Callao, where a permanent armed presidio was created, and by the formation of militias of private citizens of diverse racial origins, trades and professions. By the end of the 17th century, these processes were increasingly demonstrating the Crown's reluctance to finance local Peruvian defences with Peruvian silver, and a local awareness of the divergent interests of Crown and colony, resulting in expressions of dissatisfaction and neglect in Lima.