Colonial Argentina is designated as the period of the History of Argentina when it was an overseas colony of the Spanish Empire. It begins in the precolumbian age of the indigenous peoples of Argentina, with the arrival of the first Spanish conqueror.
When Spain and Portugal noticed that the Americas were not the Indies but a new and unknown continent, they settled the portions with the Treaty of Tordesillas, dividing an eastern section of South America for Portugal and the rest for Spain. However, most of the geography of the Americas was still unknown, and many navigators sought a passage to the East Indies rather than exploring the Americas.
The voyage of Ferdinand Magellan continued towards the south, passed the Strait of Magellan and eventually completed the first circumnavigation of the world.
The first navigators of the Americas through unexplored territories, navigated into the wide Río de la Plata expecting to find a passage to the west and reach Asia, new navigations were fostered by the rumors of silver sources (such rumors are one of the early reasons of the name of Argentina).
There were land expeditions coming from the north as well, from Lima. However, the lack of precious metals in the area, and the absence of local empires like the Aztects in Mexico or the Incas in Peru, did not allow a notable growth of the Spanish populations in the area.
The first European to disembark in what is now present day Argentina was Juan Díaz de Solís, who discovered the Río de la Plata. Solís was killed by Charrúas, along with other sailors, and his fleet returned to Spain.
The sailor Francisco del Puerto, part of Solís' voyage, was spared by the Charruas because of his young age, and stayed on the Americas for some years.
Francisco del Puerto was rescued by the Venetian Sebastian Cabot, and told him about myths of sources of silver in the area. This promoted further explorations in the area. There was no silver, nor any other precious metal, but those initial myths influenced the modern name of Argentina.