Alvise Cadamosto (c. 1432 – 16 July 1483) was a Venetian explorer and slave trader, who was hired by the Portuguese prince Henry the Navigator and undertook two known journeys to West Africa in 1455 and 1456, accompanied by the Genoese captain Antoniotto Usodimare. Some have credited Cadamosto and his companions with the discovery of the Cape Verde Islands and the points along the Guinea coast from the Gambia River to the Geba River (in Guinea-Bissau), the greatest leap in the Henrican discoveries since 1446. Cadamosto's accounts of his journeys, including his detailed observations of West African societies, have proven invaluable to historians.
Alvise was born at the Ca' da Mosto, a palace on the Grand Canal of Venice from which his name derives. His father was Giovanni da Mosto, a Venetian civil servant and merchant, and his mother Elizabeth Querini, from a leading patrician family of Venice. Alvise was the eldest of three sons, having younger brothers Pietro and Antonio.
At a remarkably young age, Alvise was cast out as a merchant adventurer, sailing with Venetian galleys in the Mediterranean. From 1442 to 1448, Alvise undertook various trips on Venetian galleys to the Barbary Coast and Crete, as a commercial agent of his cousin, Andrea Barbarigo. In 1451, he was appointed noble officer of the marine corps of crossbowmen on a galley to Alexandria. The next year, he served the same position on a Venetian galley to Flanders. Upon his return, he found his family disgraced and dispossessed. His father, caught in a bribery scandal, had been banished from Venice, and taken refuge in the Duchy of Modena. His Querini relatives took the opportunity to seize possession of his family's property. This setback marred the future prospects of Cadamosto's career in Venice, and probably encouraged his spirit of adventure, hoping to restore his family name and fortune with great feats of his own.
In August 1454, at the age of 22, Alvise and his brother Antonio embarked on a Venetian merchant galley, captained by Marco Zen, destined for Flanders. On the outward journey, the galley was detained by bad weather near Cape St. Vincent, Portugal. While waiting for the weather to improve, the Portuguese Prince Henry the Navigator, who had his seat nearby at Sagres, dispatched a couple of his commercial agents, led by his secretary Antão Gonçalves and the local Venetian consul Patrizio di Conti, to interest the stranded Venetian merchants in opening trade contracts for sugar and other goods from the prince's Madeira island. Informed by the visitors of Henry's recent discoveries in Africa, Cadamosto, "inflamed with the desire of visiting these newly discovered regions", immediately applied to Prince Henry at his residence at Raposeira to undertake an expedition on his behalf. Henry hired him on the spot.
(Note: the 16th-century Portuguese chronicler Damião de Góis, uniquely among historians, mistakenly asserted that Cadamosto's encounter took place in 1444 rather that 1454. Given the eminence of Góis, this erroneous dating has been cited by others, and has been a cause of much confusion for later histories and chronologies.)
Alvise Cadamosto set out on 22 March 1455 on a 43-tonne caravel supplied by Prince Henry, with Vicente Dias as ship master He proceeded to Porto Santo and Madeira, and thereafter weaved his way through the Canary islands, making stops in La Gomera, El Hierro and La Palma before reaching the African coast around Cape Blanc. Cadamosto made note of the existence of the Portuguese factory-fort at Arguin, but does not seem to have stopped there himself.
Cadamosto cruised down the west African coast to the mouth of the Senegal River (which he calls the Rio do Senega, the first recorded use of that name.) He does not seem to have stopped here, his destination being further south, at an anchorage point along the Grande Côte he called the Palma di Budomel (location uncertain, probably around Mboro, 15°09′42″N 16°55′45″W). Cadamosto notes that this spot (or resgate) was already used by Portuguese traders. He dates that trade between the Portuguese and the Wolof people of the Senegal region was opened around 1450 ("five years before I went on this voyage").
While at the anchorage, Cadamosto was surprised to be met by the ruler himself, the Damel of Cayor (whom he calls Budomel), accompanied by his retinue. The Damel invited him inland while the details of the trade were finalized. Cadamosto spent nearly an entire month in an inland village, hosted by the prince Bisboror (Budomel's nephew), during which time he delighted in observing much about the local country and customs.
His trade in Cayor completed, Cadamosto decided to cruise further down the coast, towards the Cape Vert peninsula. This was intended as a pure exploratory jaunt, "to discover new countries" beyond the Cape, more specifically the mysterious "kingdom called Gambra", where Prince Henry had heard (from earlier slave captives) that gold was found in abundance. Around Cape Vert, in June 1455, Cadamosto came across two Portuguese caravels, one of which was commanded by Antoniotto Usodimare, a Genoese captain in Prince Henry's service, the other by an unnamed squire of Henry's household. They agreed to join forces and proceeded south together.
After a brief fishing stop on some unnamed islands (probably Îles des Madeleines), Cadamosto, Usodimare and the Portuguese squire sailed south, down the Petite Côte until they reached the Sine-Saloum delta, a stretch inhabited by the Sereri (Serer people). Cadamosto has nothing good to say about the Serer, characterizing them as savage idolaters "of great cruelty" (although we should note at this point his information is being drawn principally from Wolof interpreters). Cadamosto claims he was the one who named the Saloum River as the Rio di Barbacini, the name by which it would remain known on European maps thereafter. Cadamosto and Usodimare tried to put in there, but quickly decided against it when an interpreter they landed to make contact with the local Serer natives gathered on the beaches was killed on the spot.
Pressing south, Cadamosto and Usodimare finally discovered the mouth of the Gambia River in late June or early July 1455. They set about sailing upriver, but their advance faced unremitting hostility from the Mandinka inhabitants upriver. Subjected to intense missile fire, they barely fended off a massed canoe attack that sought to trap and board them. According to Cadamosto's interpreters, the Mandinka believed the Portuguese were cannibals, that they had come to the region to buy black men to eat. Urged by their frightened crews, Cadamosto decided to call off venturing further and backed out of the river. Cadamosto does not supply details of the return trip to Portugal.
At the mouth of the Gambia, Cadamosto made a note of the near-disappearance of the northern Pole Star on the horizon, and roughly sketched a bright constellation to the south, believed to be the first known depiction of the Southern Cross constellation (albeit wrongly positioned by the printer and with too many stars – a more accurate rendition would have to wait until Mestre João Faras in 1500.) Cadamosto called it the carro dell' ostro (southern chariot).
While it is clear that Cadamosto traded in Cayor for slaves, it is unlikely that he sojourned for exploratory adventures south on a caravel carrying human cargo. At least there is no suggestion in his account that he was carrying a shipload of slaves at the time. It is most likely that after the terms were negotiated, Cadamosto had to wait for some time for the Damel of Cayor (or the slave traders he had contracted with) to assemble and deliver the enslaved persons. Cadamosto likely undertook the exploratory southern journey during this waiting period, and probably stopped again at Cayor to finally pick up the enslaved persons on his return to Portugal. But this is conjectural, as Cadamosto gives no details of his return journey.