Why did some Spanish sailors and officials oppose Ferdinand Magellan’s command of the expedition?

The Spanish seafaring community and various officials strongly opposed Ferdinand Magellan’s command primarily because he was a Portuguese navigator leading a Spanish-funded expedition. This resentment was fueled by several key factors:1

• National Allegiance: Many in the Spanish maritime community were outraged by Magellan’s transfer of allegiance from Portugal to Spain, viewing the project with deep suspicion.1
• Institutional Obstruction: Juan Rodríguez de Fonseca, the bishop of Burgos and head of the Casa de Contratación (House of Commerce), actively hindered the organization of the voyage. His influence led to repeated delays and attempts to undermine Magellan’s authority.1
• Portuguese Interference: Agents of the Portuguese crown, also angered by Magellan’s defection, made unsuccessful attempts to sabotage the project entirely.1
• Internal Conflict: Due to this pressure, the number of Portuguese sailors allowed on the expedition was strictly limited, and Fonseca successfully installed a Spanish officer as a cocommander to monitor Magellan. These tensions between Portuguese and Spanish officers persisted throughout the voyage, eventually resulting in severe disciplinary issues and a serious mutiny by Spanish captains.12