Why did Spain, and not Italy, fund Christopher Columbus's voyage?

Queen Isabella and King Ferdinand only agreed to fund Christopher Columbus’s voyage after several attempts by the voyager to secure their support.

Columbus came up with the idea that a new route to Asia could be discovered by sailing west across the Atlantic. However, his distance calculations were overly ambitious, which made them questionable and unbelievable. He tried pitching his idea to the Portuguese, but they declined because of the calculations. 

Early attempts to convince...

Queen Isabella and King Ferdinand only agreed to fund Christopher Columbus’s voyage after several attempts by the voyager to secure their support.

Columbus came up with the idea that a new route to Asia could be discovered by sailing west across the Atlantic. However, his distance calculations were overly ambitious, which made them questionable and unbelievable. He tried pitching his idea to the Portuguese, but they declined because of the calculations. 

Early attempts to convince the Spanish also failed. It took the intervention of King Ferdinand to allow Columbus to proceed with the journey. The king was motivated by the fact that a new trade route to Asia would help improve Spain’s status as a world power. There was also the fear that Columbus could pitch the idea to another country and that they would agree to the plan. The leadership also had the desire to spread Christianity. Spain had better access to the Atlantic than Italy, and the country was more likely to support the idea than Italy, based on logistics and the financing required.