Capitulations of Santa Fe
Having taken Granada, Queen Isabella and King Ferdinand of Spain agreed to back Columbus’s westward voyage and set the titles and share he would receive.

Jl FilpoC · CC BY-SA 4.0 · Source
For nearly ten years Columbus looked for a sponsor, arguing that sailing west across the Atlantic would reach Asia. John II of Portugal turned him down because he had made the Earth far too small, and Spanish scholars objected for the same reason. His figures were indeed wrong — had the Americas not lain between Europe and Asia, his ships would have run out of food long before arriving.
When Granada fell in January 1492, Queen Isabella summoned him again. Under the agreement signed on 17 April at Santa Fe, the camp town before Granada, Columbus was to become admiral, viceroy and governor of any lands he found and to receive a tenth of their revenues. These sweeping terms later became the subject of a long dispute between Columbus and the crown.
