Final answer:
The Portuguese voyages offered economic gains from trade in spices, silks, and African resources, religious fulfillment in finding Prester John's kingdom, and strategic alliances against Islam. The real lesson of medieval maps was that the ocean was a dangerous and unknown realm, possibly created by the Devil.
Step-by-step explanation:
The possible rewards from the Portuguese voyages during the medieval era were multi-faceted. The expeditions aimed at finding a sole water route to the East for importing lucrative items like spices, silks, and cottons at lower costs, as they were expensive due to Arab middlemen on overland routes. Additionally, the Portuguese sought to gain access to Africa's wealth, which included gold, ivory, palm oil, and the opportunity to engage in the slave trade. They were also motivated by religious purposes, such as searching for the mythical Christian kingdom of Prester John to form an alliance against Islam.In response to the question about the lesson conveyed by most medieval maps regarding the ocean, the correct answer is b) The ocean was a treacherous and unknown territory created by the Devil. Maps of the era, influenced by superstitions, often depicted the sea as a domain of horrific creatures and diabolical forces, reinforcing the perception of the ocean as a realm of danger and the unknown.