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.
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?
Portuguese expeditions organized by Prince Henry had greatly extended Portuguese maritime knowledge, but had little profit to show for the effort.
What happened after Henry's death in exploration before Vasco da Gama?
After Henry's death in 1460, the Portuguese Crown showed little interest in continuing this effort and, in 1469, licensed the neglected African enterprise to a private Lisbon merchant consortium
What was the result of neglection of the African enterprise with Vasco da Gama?
Within a few years of neglection of the African enterprise, captains expanded Portuguese knowledge across the Gulf of Guinea, doing business in gold dust, melegueta pepper, ivory and slaves.

Question: What was the most profitable trade?
Self-contained rewrite: What was the most profitable trade during exploration before Vasco da Gama?