Answer:
At the time of the fall of Constantinople to the Ottomans, the trade route through the Middle East to China and India was closed for the Christian European nations. Due to this situation, all the European powers, especially Spain and Portugal, began to look for alternative routes through which to access these markets.
In the case of the Portuguese, they began their exploration to the east, surrounding the African continent to reach the Indian Ocean through it. Thus, they began to establish colonies along their routes, both in Africa (Angola, Cape Verde, etc.) and in Asia (Goa, Macao, etc.). In this way, through the establishment of commercial posts, the Portuguese began to dominate these routes territorially, charging passage fees and establishing fixed posts in which they developed trade with the nations of the region.
