The Line of Demarcation was an imaginary line that was settled by the Portuguese and Spanish that divided the world into two parts between these two nations. First, the line was defined by Pope Alexander VI in 1493 and it changed to have its more common definition in 1494 by the Treaty of Tordesillas. The line determined that Spain controlled the lands that were discovered west of the line and Portugal controlled new lands to the east.
They wanted America to be a free country, so they encouraged people to come here for a fresh start. They wanted them to be able to be fre in what they chose to do.
People still follow this because there are people today who come here to do exactly that.
