Final answer:
Spain and Portugal agreed to the Line of Demarcation in the Treaty of Tordesillas in 1494, dividing the Atlantic Ocean and influencing territorial claims in the Americas, Africa, and Asia.
Step-by-step explanation:
The two European powers that agreed to the Line of Demarcation were Spain and Portugal. This agreement was formalized in the Treaty of Tordesillas in 1494, which awarded land to both countries by dividing the Atlantic Ocean.
The line was initially set one hundred leagues west of the Cape Verde Islands but was renegotiated to nearly 2,000 miles west, allowing Portugal to claim territories including present-day Brazil. Through this treaty, Spain gained rights to most of the Americas to build its empire, while Portugal gained trading power in Africa and Asia.