Diogo Cão was a Portuguese explorer and one of the most remarkable navigators of the epic poem of the discoveries, who made two voyages sailing along the west coast of Africa in the 1480s.
He was born in Vila Real (some say in Évora), at the middle of the 15th century, ca 1450, the illegitimate son of Álvaro Fernandes/Gonçalves Cão, Nobleman of the Royal Household, himself the illegitimate son of Gonçalo Cão.
He was the first European known to sight and enter the Congo River and to explore the West African coast between Cape St Catherine and Cape Cross almost from the equator to Walvis Bay. When King John II of Portugal revived the work of Henry the Navigator, he sent out Cão (about midsummer (?) 1482) to open up the African coast still further beyond the equator. The mouth and estuary of the Congo was now, discovered (perhaps in August 1482), and marked by a Padrão, or stone pillar (still existing, but only in fragments) erected on Shark Point, attesting the sovereignty of Portugal; the great river was also ascended for a short distance, and intercourse was opened with the natives of the Bakongo kingdom. Cão then coasted down along the present Angola (Portuguese West Africa), and erected a second pillar, probably marking the termination of this voyage, at Cape Santa Maria (the Monte Negro of these first visitors). He certainly returned to Lisbon by the beginning of April 1484, when John II ennobled him, made him a cavalleiro of his household (he was already an escudeiro or esquire in the same), and granted him an annuity and a coat of arms (April 8, 1484 and April 14, 1484). In the return he discovered the Island of Annobon.
That Cão, on his second voyage of 1484-1486, was accompanied by Martin Behaim (as alleged on the latters Nuremberg globe of 1492) is very doubtful; but we know that the explorer revisited the Congo and erected two more pillars beyond the furthest of his previous voyage, the first at another Monte Negro, the second at Cape Cross, this last probably marking the end of his progress southward, advancing 1,400 more kilometers. According to one authority (a legend on the 1489 map of Henricus Martellus Germanus), Cão died off Cape Cross; but João de Barros and others make him return to the Congo, and take thence a native envoy to Portugal. The four pillars set up by Cão on his two voyages have all been discovered in situ, and the inscriptions on two of them from Cape Santa Maria and Cape Cross, dated 1482 and 1485 respectively, are still to be read and have been printed; the Cape Cross padrao is now at Kiel (replaced on the spot by a granite facsimile); those from the Congo estuary and the more southerly Monte Negro are in the Museum of the Lisbon Geographical Society.
Navegador e explorador português (?-1486). Nada se sabe a respeito de suas origens. Os primeiros registros de sua existência datam do início da década de 1480, quando o rei Afonso V encarrega o filho, príncipe João, de supervisionar o comércio entre Portugal e Guiné e de explorar a costa da África. Quando João assume o trono, com o nome de João II, ordena novas viagens de descobrimento para chegar até o extremo sul do continente africano.
Os navegadores recebem pilares de pedra (padrões) para ser colocados em cada localidade, como marcas de posse da Coroa portuguesa. Um dos capitães da frota é Diogo Cão. Primeiro europeu a atingir a foz do rio Congo, em agosto de 1482, deixa ali um padrão e segue viagem até o cabo de Santa Maria, na costa de Angola; ali coloca a segunda marca do reino de João II. Volta a Lisboa em 1484, onde é recebido pelo rei, que o autoriza a desenhar dois pilares em seu brasão de armas, em reconhecimento pelos dois que deixara na costa africana. Na segunda viagem (1485-1486), chega até o cabo Cruz, na costa da Namíbia, de onde retorna a Portugal, após uma arriscada jornada. Desapontado por não atingir o oceano Índico, afasta-se da frota real. O local de sua morte é desconhecido.