The Treaty of Tordesillas (1494) was an agreement which divided the non-Christian world into two zones of influence, one for Spain and the other for Portugal.
In 1493 the pope attempted to settle a dispute between Spain and Portugal by giving the New World to Spain and India and Africa to Portugal. The Treaty of Tordesillas formalized this agreement with a key change that shifted the demarcation line to a circle, which enabled Portugal to claim Brazil also.