In the travel log of Vasco da Gama's journey to India in 1498, written presumably by a certain crewmember called Álvaro Velho, is noted how at a certain point in their journey in the middle of the southern Atlantic, having passed the Cape Verde Archipelago and on their way to the Cape of Good Hope, they noticed birds, algae and fish on the surface of the sea. The Portuguese would have known these to be signs of land, but how to explain the fact that Vasco da Gama took an entirely different route than the one taken by his predecessor, Bartolomeu Dias?

Evidently the path taken by da Gama reveals that the Portuguese would have done additional reconaissance in the south Atlantic between the voyage of Dias in 1488 and Gama's in 1498, through which they would have witnessed the Southern Atlantic gyre pattern of winds, but whose records were sadly lost.

The evidence comes from a certain book written in 1506, called Esmeraldo de Situ Orbis, a manuscript written by a notable Portuguese cosmographer and navigator, Duarte Pacheco Pereira, who intended to compile for King Manuel I of Portugal the most important geographical locations, coordinates, navigational details of vital interest to the Portuguese, which had been lost for nearly 400 years.

In the second chapter of the first part, Pereira is cited as having written:

Thus, fortunate Prince, we know and seen how in the third year of your rule, year of our Lord 1498, Your Highness ordered us to discover the western part, beyond the greatness of the Ocean Sea, where so great a landmass is found, with many great adjacent islands to it [...] and is greatly inhabited. So much does it's greatness stretch, that each end has not been seen nor known where it ends. In it many fine brazilwood is found, along with many other things which the ships come greatly loaded to these Kingdoms.