The early modern period supposed the expansion of the European empires in a global scale. With this idea in mind, in my future dissertation, I plan to study the process of the conquest and colonization of the Amazon Forest during the period of the European expansion in America. Related to this conquest, one aspect that catches my attention is the formation of borders between the kingdoms of Spain and Portugal in the Amazonian area. These borders were established very late in the eighteen century through the “Treaty of San Ildefonso” in 1777. The reason for this treaty, among others, was that both empires, Spain and Portugal, never completely dominated the Amazon. In fact, the disputed territory became known as the “border of clay”. Two centuries earlier, in the sixteenth-century, Philip II of Spain had released an order to prohibit the exploration of the Amazon Forest. All of this proves that the way to the Amazon was always problematic. Consequently, the main objective of my pre-dissertation project is to review some documents in the Archive of the “Univesidad del Cauca”, in Colombia, the Archive of “la Ciudad de Quito”, in Ecuador, and the Historical Archive of Belem do Para“”, in Brasil, in order to understand this complex historical problem. Some of the questions that I plan to explore with this preliminary research include the following: how was the Amazon Forest represented in the colonial period? And how were the political relations between the early modern empires and the impenetrable and dense zones of the Amazon?