A forgotten colonial skirmish over a single gunshot radius in South America
Between 1735 and 1737, Spain and Portugal engaged in a localized conflict over the Banda Oriental, modern-day Uruguay. Driven by trade disputes and territorial claims, the war centered on the Sacramento Colony, where Spain demanded the Portuguese limit their presence to a mere two-kilometer radius, sparking a two-year military standoff.
The conflict was rooted in the Treaty of Tordesillas of 1494, which Spain used to justify its claims over the region. However, Portugal had established the Sacramento Colony in 1680. Despite Spain capturing the city in 1681 and 1705, the Treaty of Utrecht in 1713 forced its return. By the 1730s, Portuguese expansion around the colony threatened Spanish trade interests, which were already burdened by heavy taxes imposed through the Viceroyalty of Peru. Spain viewed this Portuguese activity as illegal contraband, leading Captain-General Miguel de Salcedo y Sierraalta to receive orders in March 1734 to restrict the colony to a gunshot distance of roughly 2 km.
Hostilities escalated in 1735 after Spanish ships seized Portuguese vessels. On April 19, José Patiño ordered an attack on Sacramento. Salcedo led a force of 1,500 men, bolstered by 4,000 Guaraní warriors from Jesuit Reductions, beginning a siege on October 14, 1735. The Portuguese governor, António Pedro de Vasconcelos, defended the site with 900 men. Although Spain attempted a naval blockade, Portugal secured naval superiority after José da Silva Pais dispatched reinforcements, including six ships on January 6 and twelve more shortly thereafter.
The war remained a relatively small-scale affair, involving only a few thousand men on each side. Throughout 1736 and 1737, the conflict saw sporadic naval confrontations and a failed Portuguese siege of Montevideo on September 6, 1736. Ultimately, diplomatic pressure from France, Great Britain, and the Dutch Republic led to a treaty on March 16, 1737. By September, the siege of Sacramento was lifted, Spanish forces withdrew, and Salcedo was removed from his position as governor of Buenos Aires, leaving the territorial status quo largely unchanged.
