Inter caetera

Inter caetera ("Among other [works]") was a papal bull issued by Pope Alexander VI on 4 May 1493, which granted to Spain (the Crowns of Castile and Aragon) all lands to the "west and south" of a pole-to-pole line 100 leagues west and south of any of the islands of the Azores or the Cape Verde islands.

It remains unclear to the present whether the pope was issuing a "donation" of sovereignty or a feudal infeodation or investiture. Differing interpretations have been argued since the bull was issued, with some arguing that it was only meant to transform the possession and occupation of land into lawful sovereignty. Others, including the Spanish crown and the conquistadors, interpreted it in the widest possible sense, deducing that it gave Spain full political sovereignty.

The Inter caetera bull and others similar to it, particularly Dudum siquidem, made up the Bulls of Donation.

Before Christopher Columbus received support for his voyage from Queen Isabella and King Ferdinand of Spain, he had first approached King John II of Portugal. The queen's scholars and navigators reviewed Columbus's documentation, determined that his calculations grossly underestimated the diameter of the Earth and thus the length of the voyage, and recommended against subsidizing the expedition. Upon Columbus's return from his first voyage to the Americas, his first landing was made in the Portuguese Azores; a subsequent storm drove his ship to Lisbon on 4 March 1493. Hearing of Columbus's discoveries, the Portuguese king informed him that he believed the voyage to be in violation of the 1479 Treaty of Alcáçovas. The treaty had been ratified with the 1481 papal bull Aeterni regis, which confirmed previous bulls of 1452 (Dum diversas), 1455 (Romanus Pontifex), and 1456 (Inter caetera), recognizing Portuguese territorial claims along the West African coast. It was the King's understanding that the terms of the treaty acknowledged Portuguese claims to all territory south of the Canaries (which had been ceded to Spain).

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