In OTL Portugal and Castile made a certain number of treaties to estabilish their official zones of influence in Africa, Asia and America, the most famous being Tordesillas. The first of those treaties was Alcáçovas, that treaty said that future lands discovered in the Atlantic south of the 27th parallel would be portuguese, Tordesillas had a different result and divided the Atlantic with a not so well defined meridian, East of the line for Portugal and West for Castile.
The question is what if the Treaty of Tordesillas or another treaty later, but not after 1540, in addition to the Tordesillas Line of OTL created another imaginary line? One that would coincide with the parallel that pass over the southernmost point of Metropolitan Portugal, in other words it would be the paralell 36° 57' 35.7" N (or ~36.96ºN in Google Maps)? The treaty would make everything north of that line also Portuguese, adding that zone with the zone east of the OTL line, the rest would continue to be under the Spanish.
Just to make it easier to visualize such line, the mentioned parallel makes landfall in America just south of Willoughby Spit, Norfolk, VA, following a path just 4 to 5 kilometers south of the parallel 37ºN that IOTL is the line that defines the border between Colorado and Arizona, and other state borders too. Let's say that for whatever reason Portugal was able receive such cession from Spain, how history would change?
The question is what if the Treaty of Tordesillas or another treaty later, but not after 1540, in addition to the Tordesillas Line of OTL created another imaginary line? One that would coincide with the parallel that pass over the southernmost point of Metropolitan Portugal, in other words it would be the paralell 36° 57' 35.7" N (or ~36.96ºN in Google Maps)? The treaty would make everything north of that line also Portuguese, adding that zone with the zone east of the OTL line, the rest would continue to be under the Spanish.
Just to make it easier to visualize such line, the mentioned parallel makes landfall in America just south of Willoughby Spit, Norfolk, VA, following a path just 4 to 5 kilometers south of the parallel 37ºN that IOTL is the line that defines the border between Colorado and Arizona, and other state borders too. Let's say that for whatever reason Portugal was able receive such cession from Spain, how history would change?