How did Christopher Columbus secure funding for his expedition?

Christopher Columbus secured funding for his expedition primarily by appealing to the desire to spread Christianity. This was a significant aspect of his proposals to Queen Isabella and King Ferdinand of Spain. During the time of Columbus's voyages, there was a strong interest in spreading Christianity, particularly in the context of the Reconquista, which was the effort to reclaim land from Muslim control in Spain. Columbus promised the monarchs not only riches from new lands but also the conversion of indigenous people to Christianity, which aligned well with the religious goals of the Spanish crown.

Columbus’s approach combined both the promise of new resources and the religious aspect, making his proposal appealing to the Spanish rulers who were eager to expand their influence and power. While other factors like the search for gold and securing private investors were also relevant, it was his emphasis on spreading Christianity that played a critical role in winning the royal support for his journey across the Atlantic.