Queen Isabel and King Fernando agreed to Columbus's conditions that if he succeeded with his first voyage, then he would be knighted, appointed Admiral of the Ocean Sea, made the viceroy of any new lands, and get ten percent of any new wealth. So observers think that the Spanish monarchs did not expect Columbus to return, and that is why they acceded to his conditions.
Following his return from his successful voyage of discovery, the Spanish sovereigns granted Columbus the right to bear arms. According to the letters patent dated May 20, 1493, Columbus was to bear in the first and the second quarters the royal charges of Castile and Leon -- the castle and the lion. In the third quarter would be islands in a wavy sea (he later added a continent to the islands), and in the fourth, the customary arms of his family ( he later changed this to five anchors in fess from the blazon of the Admiral of Castile)
By 1502, after his 3rd voyage, Columbus had been charged with mal administration in the Indies.The Book of Privileges is a collection of agreements between Columbus and the crowns of Spain prepared in Seville in 1502 before his 4th final voyage. The documents include the 1497 confirmation of the rights to titles and profits granted to the Admiral by the 1492 contract of Santa Fe and augmented in 1493 and 1494, as well as routine instructions and authorizations related to his third voyage. We know that four copies of his Book of Privileges existed in 1502, three written on vellum and one on paper. It includes an unofficial transcription of a Papal Bull of September 26, 1493 in which Pope Alexander VI extended Spain's rights to the New World.
Columbus' life from 1492 covers his 4 voyages and his life in Spain after his last voyage.
Christopher Columbus, discoverer of the Americas