Background:
The Río de la Plata River Plate is the estuary formed by the confluence of the Uruguay and the Paraná rivers. It empties into the Atlantic Ocean, forming a funnel-shaped indentation on the southeastern coastline of South America. Depending on the geographer, the Río de la Plata may be considered a river, an estuary, a gulf or a marginal sea.
The Río de la Plata was first explored by the Portuguese in 1512–13. The Spanish first explored it in 1516, when the navigator Juan Díaz de Solís traversed it during his search for a passage between the Atlantic and the Pacific Oceans, calling it the Mar Dulce, or freshwater sea. The Portuguese navigator Ferdinand Magellan briefly explored the estuary in 1520 before his expedition continued its circumnavigation, and in 1521 Cristóvão Jacques also explored the Plate River estuary and ascended the Parana River for the first time, entering it for about 23 leagues (around 140 km) to near the present city of Rosario. The area was also visited by Francis Drakes fleet in early 1578, in the early stages of his circumnavigation.
Explorer Sebastian Cabot made a detailed study of the river and its tributaries and gave it its modern name. He explored the Paraná and Uruguay rivers between 1526 and 1529, ascending the Paraná as far as the present-day city of Asunción, and also explored up the Paraguay River. Cabot acquired silver trinkets trading with the Guaraní near todays Asunción, and these objects (together with legends of a Sierra de la Plata in the South American interior brought back by earlier explorers) inspired him to rename the river Río de la Plata (River of Silver).
The first European colony was the city of Buenos Aires, founded by Pedro de Mendoza on 2 February 1536. This settlement, however, was quickly abandoned; the failure to establish a settlement on the estuary led to explorations upriver and the founding of Asunción in 1537. Buenos Aires was subsequently refounded by Juan de Garay on 11 June 1580.
During the colonial era the Río de la Plata was made the center of the Governorate of the Río de la Plata, but the region\'s development was largely neglected by the Spanish Empire until the 1760s, when Portugal and Britain threatened to expand into the estuary. The governorate was elevated to form the Viceroyalty of the Río de la Plata in 1776. In 1806 and 1807 the river was the scene of an important British invasion that aimed to occupy the area.
Conflict in the region intensified after the independence of the former Spanish and Portuguese colonies in the first quarter of the 19th century. Interests in the territories and the navigation rights over the Platine region played a major role in many armed conflicts throughout the century, including the Argentine civil wars, the Cisplatine and Platine wars, and the Paraguayan War. The river was blockaded by extra-regional powers 1838–1840 and 1845–1850.

Bonne, Rigobert 1729-1795
Bonne was one of the most important cartographers of the late 18th century.
In 1773 Bonne succeeded Jacques Nicolas Bellin as Royal Cartographer to France in the office of the Hydrographer at the Depôt de la Marine. Working in his official capacity, Bonne compiled some of the most detailed and accurate maps of the period. Bonne’s work represents an important step in the evolution of the cartographic ideology away from the decorative work of the 17th and early 18th century towards a more detail oriented and practical aesthetic. With regard to the rendering of terrain Bonne maps bear many stylistic similarities to those of his predecessor, Bellin. However, Bonne maps generally abandon such common 18th century decorative features such as hand coloring, elaborate decorative cartouches, and compass roses.
While mostly focusing on coastal regions, the work of Bonne is highly regarded for its detail, historical importance, and overall aesthetic appeal.