Christopher Columbus

Columbus tried to convince King John II of Portugal to his ideas, but he sent him back to his advisors, who rejected his plan.

An excerpt from the article 26 facts about Christopher Columbus
Confronted with this, Columbus moved to Spain in 1485, where his ideas were heard by the royal court. They could not be implemented until Spain dealt with the Reconquista (the struggle of the Christians to expel the Moors from the Iberian Peninsula) in 1492.