Generally, even though they were trained warriors, conquistadors were mostly poor nobles in search for gold and their main goal was to find gold. They also had as objectives claim as much land as they could and spread "the word of god". That search for gold ended up being the reason of a lot of speculation and "adventures" for legendary cities. One of them being Cipango, "the place where gold was born". It was not uncommon for the conquistadors to chase after such legendary places.