How did Islam, the Crusades, and the Black Death directly or indirectly led to the rise of Spanish and Portuguese maritime exploration in the late 1400s and early 1500s?

The development of Islam, the Crusades and the black plague were crucial factors that directly and indirectly influenced the maritime exploration by Portugal and Spain in the 1400s and 1500s.

The expansion of Islam, which emerged in Arabia, meant that Muslims took control of large numbers of trade routes. This motivated the European kingdoms to carry out different confrontations to recover these territories, such as the Spanish Reconquest or the Crusades towards the Holy Land, among others. In all cases, they were Christian European armies, against Islamic forces from the Middle East.

In turn, these military clashes also involved cultural and social exchanges, generated from the establishment of European kingdoms in the Middle East, and through the development of the Silk Road as the main commercial route of the time. This contact generated the breeding ground for the development of the Black Death, a pandemic that devastated Europe in the 1300s, closing the borders with the east.

Finally, to the tension between the religions and the Black Death was added the fall of Constantinople in 1453 at the hands of the Ottomans, a Muslim empire that came to control the main passage between Europe and the East.

All these situations, added together, gave rise to the need to find new routes to China and India, the main import and export markets of the time, avoiding going through the routes controlled by the Muslims. Thus, the European nations began to explore the seas.