I intend to explore this topic through four perspectives:
What were the political drivers for what was a costly national undertaking? Was it a deliberate strategy?
What was the economic motivation for pursuing trade so far from Portugal?
How did Portuguese society organize itself to support this endeavour? Were there aspects of Portuguese society that facilitated this adventurism? How did society change as a result?
What gave Portugal the technological ability to explore so far from its own shores? How did communications and supply chains work?
These perspectives naturally overlap; religion, for example, was a major factor and it cut across both the political and social lenses.
According to historian Sanjay Subrahmanyam, it was the Portuguese historian Vitorino Magalhães Godinho who introduced in the 1960s the notion that Portugal's imperial project was above all mercantile and rational – to build an empire on commercial exchanges to control the trade of pepper and other spices, the traditional flow of which had been cut off in the eastern Mediterranean by the Mamluks and the Ottomans. Godinho claimed, in this materialist interpretation, that there was no cultural project and downplayed the religious motives. Later historians would argue that things were, in fact, much messier. The "Age of Discoveries" was also a period of rabid anti-Islamism and messianic beliefs, and the push towards the east, traditionally controlled by Muslims from the European perspective, was partly driven by religious sentiments.
[WIP: this post will be updated continuously]
SL