What treaty divided the non-European world between Spain and Portugal in 1494?

The Treaty of Tordesillas divided newly claimed non-European lands between Spain and Portugal in 1494. Signed at Tordesillas, Spain, on 7 June, the agreement attempted to settle a dispute created by Christopher Columbus’s voyages and competing Portuguese and Castilian claims.

The treaty placed a line of demarcation roughly 370 leagues west of the Cape Verde Islands. Lands east of the line were assigned to Portugal, while lands west of it were assigned to the Crown of Castile, which represented Spain’s overseas claims. The arrangement helped explain why Portugal later controlled Brazil while Spain claimed most of the rest of the Americas.

The treaty was negotiated by the two Iberian powers without consulting the Indigenous peoples whose lands were being divided. Its line was also difficult to locate precisely because sixteenth-century measurements of longitude and distance were uncertain. The agreement did not permanently settle every rivalry: the later Treaty of Zaragoza addressed competing Spanish and Portuguese claims in Asia. The Treaty of Tordesillas is therefore best understood as a European diplomatic division of imperial claims, not an actual legal partition accepted by the rest of the world.