“MONSTROUS AND ILLEGAL PROCEEDINGS”: LAW ...

the city remained a sparsely populated backwater. It subsisted largely on contraband traffic
with the distant Andean highlands and their vast silver deposits. 4
This began to change in the early decades of the 18 th century. Growing international
rivalries over American wealth and Atlantic trade slowly transformed the Río de la Plata’s
rivertine network into an important prize for the Iberian powers. Economic and political
conflicts over the estuary intensified noticeably when the Portuguese empire established a
military fortress at Colônia do Sacramento directly across the Río de la Plata estuary from
Buenos Aires in 1680. The outpost initially provided the Portuguese with a “backdoor” to
Andean silver. This in turn bolstered the region’s role as an artery for contraband. The
Portuguese presence and the growing drain of the smuggling economy on the imperial
treasury soon forced Spanish officials into strengthening their own position in the estuary.
The Spanish founded a rival military outpost on the Río de la Plata’s eastern shore at
Montevideo in 1726 to check the Portuguese advance.
The Portuguese responded to the growing Spanish military activity on the Río de la
Plata’s eastern edges by pushing to expand their own imperial possessions in Brazil
southwards. In 1737, the Portuguese established the first coastal settlements in what would
become the province of Rio Grande do Sul. To support development in the region, the
Portuguese crown granted large tracts of land – or sesmarias – to military officials settling in
the region. Chasing free lands, military glory and rumors of easy wealth from gold or the
capture of Indians, Portuguese settlers flowed southwards in small, but growing numbers.
Imperial boundaries had little meaning for these migrants. Their settlements extended well
into territories claimed by the Spanish. Beyond even these limits, Portuguese settlers made a
4 Even by 1750, Buenos Aires’ population was only 12,000. Sheridan, ed. Contested
Ground: Comparative Frontiers on the Northern and Southern Edges of the Spanish Empire, 6.
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