Pacific Ocean (the South Sea)
The Spaniards called it the South Sea (mar del sur). Vasco Núñez de Balboa was the first Spaniard to see it, from the Isthmus of Panama in 1513.
Today: Pacific Ocean
The Bison Plains and the People Who Follow the Herds
Pedro de Castañeda de Nájera, Account of the Journey to Cíbola (written in the 1560s), part 2, chapter 7: the plains of the bison · written in the 1560s, more than twenty years after the events; surviving copy dated 1596 (events of 1541)
agora diremos de los llanos que es una tierra llana y espaçiosa que tiene en anchura mas de quatro cientas leguas por aquella parte entre las dos cordilleras la una la que atrabeso francisco uasques coronado a la mar del sur y la otra la que atrabeso la gente de don fernando de soto a la mar del norte entrando por la florida lo que de estos llanos se bio todo era despoblado y no se pudo ber la otra cordillera ni çerro ni çierra que tubiese de altura tres estados con andar doçientas y sinquenta leguas por ellos atrechos se hallauan algunas lagunas redondas como platos de un tiro de piedra de ancho y mayores algunas dulçes y algunas de sal
Now we will tell about the plains. They are a flat, wide land, more than four hundred leagues across in that region. They lie between two mountain ranges. One is the range on the South Sea side, which Francisco Vázquez Coronado crossed. The other is the range on the North Sea side, which Don Fernando de Soto's people crossed, coming in by way of Florida. All of the plains that we saw were without settlements. We could not see the other range, or any hill or ridge even three times a man's height, though we traveled two hundred and fifty leagues across them. Here and there we found round ponds, shaped like plates, a stone's throw wide or more. Some were fresh water and some salt.