Pope Alexander VI issued the papal bull Dudum siquidem, one of the Bulls of Donation, marking the beginning of the Spanish colonization of the Americas.

Pope Alexander VI was head of the Catholic Church and ruler of the Papal States from 11 August 1492 until his death in 1503.

A papal bull is a type of public decree, letters patent, or charter issued by the pope of the Catholic Church. It is named after the leaden seal (bulla) traditionally appended to authenticate it.

Dudum siquidem was a papal bull issued by Pope Alexander VI on 26 September 1493, one of the Bulls of Donation addressed to the Catholic Monarchs Isabella I of Castile and Ferdinand II of Aragon which supplemented the bull Inter caetera and purported to grant to them "all islands and mainlands whatsoever, found and to be found, discovered and to be discovered, that are or may be or may seem to be in the route of navigation or travel towards the west or south, whether they be in western parts, or in the regions of the south and east and of India".

The Bulls of Donation, also called the Alexandrine Bulls, and the Papal donations of 1493, are three papal bulls of Pope Alexander VI delivered in 1493 which granted overseas territories to Portugal and the Catholic Monarchs of Spain.

The Spanish colonization of the Americas began in 1493 on the Caribbean island of Hispaniola after the initial 1492 voyage of Genoese mariner Christopher Columbus under license from Queen Isabella I of Castile. These overseas territories of the Spanish Empire were under the jurisdiction of Crown of Castile until the last territory was lost in 1898. Spaniards saw the dense populations of Indigenous peoples as an important economic resource and the territory claimed as potentially producing great wealth for individual Spaniards and the crown. Religion played an important role in the Spanish conquest and incorporation of indigenous peoples, bringing them into the Catholic Church peacefully or by force. The crown created civil and religious structures to administer the vast territory. Spanish men and women settled in greatest numbers where there were dense indigenous populations and the existence of valuable resources for extraction.