Pope Alexander VI issues the papal bull Inter caeterea ("among other works"), formally dividing possession of the New World between Spain and Portugal along a longitudinal line than runs 250 miles west of the Cape Verde Islands.
The exact meaning of the bull has been debated. Is it meant as a grant of sovereignty, or simply a recognition of facts on the ground — accepting the current occupation of the land as sovereignty? Spanish rulers interpret the bull Inter caeterea as broadly as possibly and use it to justify their exercise of absolute sovereignty over territory in the Western Hemisphere.
Spain and Portugal have been at odds over who should control newly found lands, and earlier papal bulls would appear to give Portugal control over North America. Pope Alexander VI is a Spaniard, though, as well as a personal friend of the Spanish king. This is more than enough reason for him to suspend the earlier papal bulls and turn most of North America over to Spain.