In lecture, it was explained that the Pope issued a Papal Bull dividing the East and West trade routes and lands between Spain and Portugal primarily for the following reason:

a. they were the strongest naval powers

b. they were the only loyal Catholic countries

c. they had the most powerful armies

d. they were the wealthiest countries in Europe at the time

they were the strongest naval powers

a. they were the strongest naval powers

Explanation:

Portugal and Spain were at the head of the European sea exploration by the end of the 15th century, especially Portugal. The Portuguese had been navigating around Africa for many decades and in the final years of the century, the Portuguese circumnavigated Africa and made it to Asia. Columbus had arrived in the New World in 1492 and Spain wanted to explore the new routes to look for gold and riches. There was a dispute over the right to explore and conquer, and the crowns of both countries appealed to pope Alexander VI, who drew a line in the middle of the Atlantic and gave Spain all the territories to be discovered west of the line, and gave Portugal all the territories found east of the line.