Why did the captains of three ships rebel against Magellan?

Ferdinand Magellan was from Portugal. The ship captains were from Spain. They hated that he was in charge of them and gave him no credit, feeling that Magellan was beneath them. Without this respect, they fomented a mutiny. Magellan swiftly retaliated and overcame the mutiny and dealt with the mutineers accordingly, either through death or abandonment.