Which 1494 treaty divided newly explored lands between Spain and Portugal?

The Treaty of Tordesillas drew a line down the Atlantic and awarded everything newly found west of it to Spain and everything east to Portugal. It followed Columbus's first voyage, when a papal ruling had granted Spain terms Portugal considered unacceptable, and the treaty moved the line further west as a negotiated compromise between the two crowns. The obvious problem is that nobody could measure longitude at sea with any accuracy, so where the line actually fell was a matter of argument for centuries. Its most lasting consequence was Brazil. The eastern bulge of South America lay on the Portuguese side, which is why Brazil speaks Portuguese while the rest of the continent speaks Spanish. The treaty also assumed that two European monarchies, with papal blessing, could allocate the inhabited world between them, an assumption that other European powers ignored entirely once they had ships of their own.

A later agreement extended a matching division on the far side of the globe, in the Pacific.