Conversation so far:
What types of exploration happened before Vasco da Gama?
Exploration before Vasco da Gama included Portuguese expeditions organized by Prince Henry the Navigator had been reaching down the African coastline, principally in search of west African riches.

Question: Were any riches found?
Self-contained rewrite: Were any riches found during the Portuguese expeditions organized by Prince Henry the Navigator had been reaching down the African coastline, principally in search of west African riches?