The Treaty of Tortoceus and the Spice Islands

In 1518, the Spanish argued that the Treaty of Tortoceus did exactly that, divide the world in half. The treaty didn't specifically say Spain gets the western half of the world, Portugal gets the eastern half. It basically says Spain goes one way, Portugal goes the other. Whatever you find is yours. And that worked for a while until it wasn't and no one really knew how big the world was.