The imaginary line was the Line of Demarcation drawn according
to the Treaty of Tordesillas in 1494. It was designed to prevent
Spain and Portugal from claiming the same regions and establishing
competing colonies in the world, notably the New World. The line
was a line of longitude around 42.5° W, about midway between the
Portuguese colony in the Cape Verde Islands and the new Spanish
possessions in Hispaniola and the Caribbean. The line effectively
limited Portugal to a major colony in Brazil, the only modern South
American country that extends east of the line.
Related Q&A：
Why was an imaginary line drawn running north and south through South America and what was this line-Well, that imaginary line is called the Equator, my friend. It was drawn to help us understand and measure different aspects of our planet. You know, it helps in geography and navigation. It divides the Earth into the Northern Hemisphere and the Southern Hemisphere. And it's not just some random line, it has real significance for things like climate and the way we study the Earth. So, that's what that line is all about! Isn't that interesting?
