Conversation so far:
What was the Conquistador?
Conquistadors were the knights, soldiers, and explorers of the Spanish Empire and the Portuguese Empire.
Why did the conquistadors resist the recall?
The conquistadors wanted to find El Dorado.
How long did Francisco Pizarro stay in South America?
Francisco Pizarro served there until 1541.
Did Francisco Pizarro set out to try again at exploring South America?
Francisco Pizarro set out on several expeditions in South America.

Question: What discovery motivated him?
Self-contained rewrite: What discovery motivated Francisco Pizarro on his exploration in South America?