why would a relatively poor nation like portugal have played such an important role in exploration?
First of all, back in the days when Portugal was an imperialist power and was sending explorers around the world, it wasn’t exactly “poor” to begin with. Compared to Britain it was wealthier in the early days of the Portuguese empire while Britain was a backwater kingdom(15th to 16th centuries) Portugal’s location also favored taking the lead in exploration. It’s close proximity to Africa and the fact that it is on the Atlantic ocean give easy access to both Africa and the Americas, especially after the Azores(a group of Atlantic islands) became Portuguese possessions.