Which 1494 treaty divided overseas spheres of influence between Spain and Portugal?

The Treaty of Tordesillas divided overseas spheres of influence between Spain and Portugal in 1494.

Negotiated with papal involvement, the treaty established a meridian west of the Cape Verde Islands. Lands discovered to the west were generally assigned to Castile, while lands to the east were assigned to Portugal.

The boundary helped explain why Brazil became Portuguese-speaking while much of the rest of South and Central America came under Spanish rule. The treaty was negotiated before Europeans understood the full scale of the Pacific and the Americas.

The later Treaty of Zaragoza, signed in 1529, addressed competing claims in Asia. The Tordesillas line was influential, but Indigenous nations were not parties to the agreement and did not surrender their own sovereignty by signing it.