The Treaty of Tordesillas was signed in 1494.
The agreement divided newly encountered and potentially undiscovered lands outside Europe between the crowns of Castile and Portugal. It established a demarcation line in the Atlantic, with territories west of the line generally assigned to Castile and those east of it to Portugal.
The treaty followed disputes arising from voyages across the Atlantic and earlier papal decisions. Its line was later associated with Portugal’s claim to Brazil, because part of Brazil lies east of the agreed boundary.
The treaty did not represent an agreement by Indigenous peoples, nor did the two kingdoms have the practical ability to map or enforce every claimed territory accurately. Spain and Portugal later signed the Treaty of Zaragoza in 1529 to address their competing claims in Asia.