Sicut Dudum, forbidding the enslavement by the Spanish of the Guanche natives in Canary Islands who had converted, or were converting to, Christianity, is promulgated by Pope Eugene IV.

Sicut dudum was a papal bull promulgated by Pope Eugene IV in Florence on January 13, 1435, which forbade the enslavement of the Indigenous Guanches people of the Canary Islands who had converted, or were converting to, Christianity and ordered, under pain of excommunication, that all such slaves be set free within 15 days.

The Guanches were the indigenous inhabitants of the Canary Islands, located in the Atlantic Ocean some 100 kilometres (60 mi) to the west of modern Morocco and the North African coast. The islanders spoke the Guanche language, which is believed to have been related to the Berber languages of mainland North Africa; the language became extinct in the 17th century, soon after the Conquest of the Canary Islands by Spain.

The Canary Islands or Canaries are an archipelago in the Atlantic Ocean and the southernmost autonomous community of Spain. They are located 100 kilometers to the northwest of the African continent. The islands have a population of 2.26 million people and are the most populous overseas special territory of the European Union.

Pope Eugene IV, born Gabriele Condulmer, was head of the Catholic Church and ruler of the Papal States from 11 March 1431 to his death, in February 1447. Condulmer was a Venetian, and a nephew of Pope Gregory XII. In 1431, he was elected pope.