The treaty of Alcacovas in 1479 said that within Africa and the Atlantic, Portugal would have the claim to any islands or lands discovered or conquered south of the latitude of the Canary Islands in the Atlantic and Africa, while Castille/Spain would have the claim to any lands newly discovered in the Atlantic or conquered in Africa from the Canary islands on north.
Thus it divided the non-European world between a Portuguese south and a Spanish north.
After the voyage and return of Columbus and in the Treaties of Tordesillas of the 1490s, this was switched around in such a way that Spain would have claim to everything west of the treaty line while Portugal would have claim to anything east of the treaty line.
Thus the combined impact of Columbus' voyage and Tordesillas was to turn the line of the treaty of alcacovas on its side.
But what if the line of the earlier treaty was retained, so that even in the America, Portugal had claim to everything south of a line while Spain had claim to the north.
Strictly speaking, if extended to the west from Africa, the Alcacovas line would slice through south Florida, south Texas and northern Mexico. However, a slight southward adjustment, tying the line to the Tropic of Cancer, would leave all of Texas and Florida in the Spanish zone.
How could things end up divided this way?
Thus it divided the non-European world between a Portuguese south and a Spanish north.
After the voyage and return of Columbus and in the Treaties of Tordesillas of the 1490s, this was switched around in such a way that Spain would have claim to everything west of the treaty line while Portugal would have claim to anything east of the treaty line.
Thus the combined impact of Columbus' voyage and Tordesillas was to turn the line of the treaty of alcacovas on its side.
But what if the line of the earlier treaty was retained, so that even in the America, Portugal had claim to everything south of a line while Spain had claim to the north.
Strictly speaking, if extended to the west from Africa, the Alcacovas line would slice through south Florida, south Texas and northern Mexico. However, a slight southward adjustment, tying the line to the Tropic of Cancer, would leave all of Texas and Florida in the Spanish zone.
How could things end up divided this way?