Why did Magellan seek to prove he set out from Spain in 1519s?

Ferdinand Magellan sought to prove he set out from Spain in 1519 to establish a westward route to the Spice Islands, which were highly coveted for their valuable spices, particularly cloves and nutmeg. By demonstrating a successful passage, he aimed to secure Spain's claim over new territories and enhance its influence in global trade. Additionally, proving the viability of this route would validate his expedition and ensure continued support and funding from the Spanish crown.