Columbus was not a disinterested explorer. He was concerned about what he and his family would get out the voyages he made. Thus he had compiled in 1502 his Book of Privileges, shortly before he left on his fourth and last voyage.
This book is rare; there are only four copies. The Library of Congress has one of the three vellum copies. You can learn more about the book here: See it Now: Columbus’s Book of Privileges | Library of Congress Blog.