Alvise Cadamosto or Alvide da Ca' da Mosto (Portuguese pronunciation: [aɫˈviz(ɨ) kɐðaˈmoʃtu], also known in Portuguese as Luís Cadamosto; c. 1432 – July 18, 1488) was an Italian slave trader and explorer, 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. Cadamosto and his companions are credited 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, Cadamosto 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 by 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 March 22, 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, ). 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"). Cadamosto had sought to trade Iberian horses for black slaves, the principal line of business at this resgate. Horses were highly valued on the Senegalese coast, and traded at a rate of between 9 and 14 slaves per horse. Cadamosto is said to have sold seven horses and some woolen goods (a total value of around 300 ducats) for about 100 slaves.
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, rather than return home with his human cargo, 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 (and probably desirous to keep his human cargo intact – he had been carrying a shipload of slaves since Cayor), 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 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).
It is known that the fleet was back in Portugal before the end of the year, as Antoniotto Usodimare would write a letter dated December 12, 1455, to his creditors back in Genoa, reporting the results of his voyage (albeit with much exaggeration, and without mentioning Cadamosto).
Cadamosto set out again from Lagos in May 1456, this time not alone, but together with Antoniotto Usodimare and another caravel with an unnamed Portuguese captain, another servant of Prince Henry. The three vessels made no known trading stops, intending to sail straight to the Gambia River (probably per Prince Henry's instructions).
Catching a storm around Cape Vert peninsula, the little fleet was forced to sail west, away from the coast for two days and three nights (about 300 miles) and stumbled on the as-yet-undiscovered archipelago of the Cape Verde Islands. Cadamosto, Usodimare and the unnamed captain scouted several of the uninhabited islands, believing them to be four in number (although Cadamosto notes in his account that later explorers would find them to be ten). They anchored first on an island which they named Buona Vista (Boa Vista), before proceeding on to a larger island, which they named San Jacobo (Santiago) (according to Cadamosto, on account of it being the feast of SS. Philip and James – probably an error) Finding the islands uninteresting, they headed on.
(Note: although Cadamosto's claims credit for the discovery of the Cape Verde islands, this is disputed by Diogo Gomes, who claims he discovered the islands, together with Antonio da Noli, in 1462 (sometimes dated 1460))
Cadamosto, Usodimare and the unnamed Portuguese captain proceeded to enter the Gambia River again, albeit this time without opposition. They sailed about 10 Italian miles (15 km) upriver and anchored briefly on a river island they named Santo Andrea (to bury a deceased crew member, named Andrea; the island is believed to be modern Dog Island).
The trio proceeded upriver carefully, warily watched by native Mandinka canoes, but this time no hostilities or ambushes emerged. Eventually, one the interpreters managed to entice some of the canoe-borne natives aboard the Portuguese ships and opened peaceful contact. The natives identified themselves as subjects of king Forosangoli (of the southern bank of the Gambia) and that he, and most other Mandinka kings along the Gambia river were all vassal subjects of the Emperor of Mali (Impatore di Melli), and that some of the local kings were willing to meet the Portuguese. Following the instructions of his interlocutors, Cadamosto sailed some 60 Italian miles up the Gambia river, reaching the residence of the Mandinka king he called Battimansa, Mandinka for "king of the Batti' (probably Badibu, on the north side of the river). They were well received, but disappointed at the little evidence of the large amounts of gold they had expected to find. They engaged in some petty trade with the locals, in particular musk (invaluable to European perfumers), and imply they even acquired live specimens of African civet cat.
Cadamosto mentions interacting with another lord, Guumimensa, whose dominion was closer to the mouth of the river. This is probably none other than the formidable 'Niumimansa', king of the Niumi-Banta of Barra region, whose rule extended over Niumi-Bato (Niominka) of the Diombos River shore, an old antagonist of Portuguese explorers. However, Cadamosto reports their relations went quite smoothly.
Cadamosto and his companions stayed in Badibu for 11 days, before departing. They did not discover the commercial center of Cantor, which was still several miles upriver (it was only discovered a couple of years later, by Diogo Gomes). But he did discover malaria, and his crew quickly fell ill with fevers. It was probably this epidemic that prompted Cadamosto to cut short his stay and leave the Gambia river, back to the ocean, where the fevers seemed to have subsided.
Resolved to continue exploring the West African coast, Cadamosto's trio set sail south, doubling Cape St. Mary ( ) and carefully navigating the dangerous breakers around Bald Cape ( ), reporting a couple of rivers along the way (none of which he names). A few days later, Cadamosto and his companions discovered the mouth of the Casamance River ( ). They named the river after the local lord Casamansa, king ('mansa') of Kasa (called Casangas by later Portuguese, a now near-extinct people, related to the Bainuk people). They sent a couple of launches to land to open contact, but being told the king was absent on campaign, Cadamosto did not linger but decided to continue on.
Sailing south, the fleet reached a red-colored headland they named Capo Rosso (Cape Roxo, , today marking the border between the republic of Senegal and Guinea-Bissau). In his account, Cadamosto names two large rivers beyond the Cape Roxo promontory – Santa Anna and San Dominico – which are a little confusing. It is believed one is likely to be the Cacheu River ( , often indicated in later Portuguese maps as Rio de São Domingos) while the other river is probably one of the branches (Rio de Jatta or Rio das Ancoras) of the Mansôa River ( )
A day later, Cadamosto discovered a great river (grandissimo fiume), which they named Rio Grande (the Geba River – more precisely, the wide estuary it forms together with the Corubal River, it doesn't seem they actually entered the river itself) ( ). After anchoring near the southern bank of the estuary, they were approached by a couple of long native canoes from the mainland (no identification given, probably Balantas or Biafares) A few trinkets were traded with the canoes, but they were unable to open communication, as their on-ship interpreters (Wolof and/or Mandinka) did not understand their native language. After a couple of days, they lifted anchor and made their way to some "of the many islands in the sea" (the Bissagos Islands), but found it just as impossible to communicate with the inhabitants there.
Given the language barrier, they saw no point in proceeding further. Cadamosto, Usodimare and the unnamed Portuguese captain set sail back to Portugal.
The record of Portuguese discoveries prior to Alvise Cadamosto did not seem to have gone beyond the Sine-Saloum delta. The furthest pre-Cadamosto seems to have been the singular expedition of Álvaro Fernandes in 1446, which may have reached as far as Cape Roxo, but this was not followed up. The 1447 expedition led by Estêvão Afonso did not go beyond the beginning of the estuary of the Gambia River, and thereafter expeditions below Cape Vert were largely suspended by Prince Henry. The principal barrier to the Portuguese seems to have been belligerence of the Niumi-Bato (Niominka) and the Niumi-Banta (Mandinka of Niumi (Barra)), both led by the same king, Niumimansa. Cadamosto encountered that hostility on his first expedition of 1455. But on his second trip, in 1456, opposition fell away for some reason, and he managed to become the first European (along with Antoniotto Usodimare and their anonymous companions) to sail up the Gambia River. It is uncertain what caused this change of attitude from one year to the next – a new Niumimansa? A shift in senegambian politics? The unreliable Diogo Gomes later boasted that he sailed to the Gambia sometime between 1456 and 1458 and single-handedly negotiated a peace with the Niumimansa, although this is likely exaggerated.)
Once they opened the Gambia River, Cadamosto and Usodimare led the next great leap of Henrican discoveries in Africa – Cape Verde islands, the Casamance River, Cape Roxo, Cacheu River and finally the Geba River and Bissagos Islands. The length of coast they discovered in 1456 was the greatest leap in the Portuguese era of discoveries since 1446. Much the same coast would be covered again by Diogo Gomes around 1458 (possibly as early as 1456, probably sent by Henry as a follow up to Cadamosto's report) and 1462. Cadamosto's furthest marker would only really be surpassed by Pedro de Sintra in 1461–62.
After his return in 1456, Cadamosto continued to live in Lagos for many years, suggesting he must have continued to engage, directly or indirectly, in West African commerce. It is not known whether Cadamosto himself made any further trips down the African coast. Cadamosto bluntly states that there were no other voyages of exploratory significance by anyone after 1456, until the expedition of Pedro de Sintra in 1462. Cadamosto acquired the details of that expedition from Sintra's clerk upon its return.
Cadamosto's patron, Prince Henry the Navigator, died in November 1460, and the monopoly on African trade reverted to the Portuguese crown and its operations were gradually transferred from Lagos to Lisbon. Probably seeing no future for himself in the new order, Cadamosto left Portugal and returned to Venice in February 1463. Cadamosto is believed to have brought notes, logs and several nautical maps with him. Cadamosto used these to compose his famous Navigationi sometime in the mid-1460s. The Navigazioni, besides generally hailing the Portuguese discoveries and lionizing Prince Henry, provided detailed accounts of three expeditions – his own voyages of 1455 and 1456, and the voyage of Pedro de Sintra in 1462. He is believed to have delivered much of his primary material to the Venetian cartographer Grazioso Benincasa, as Benincasa went on to produce an atlas in 1468, depicting the West African coast with remarkable accuracy.
The Navigationi were probably written in an effort to advertise his accomplishments, and rescue his family name. Upon his return, Cadamosto managed to recover some of his family's property from his Querini relatives and, a couple of years later, married Elisabetta di Giorgio Venier, a rich noblewoman but of frail health – she died without bearing him a child. He returned to commerce, with trading interests as far afield as Spain, Alexandria, Syria and England, and with fortune and connections restored, carved out a diplomatic and administrative career for the Republic of Venice alongside it. Cadamosto served as Venetian proveditor in Cattaro, then in Corone, and was sent on diplomatic missions to Dalmatia and Herzegovina. After the fall of Negroponte in 1470, Cadamosto was placed in charge of devising a plan for the defense of Albania against the Ottomans.
In 1481, Alvise Cadamosto was elected captain of the Venetian Alexandria galley fleet, ending his naval career on the same ships where he started. He died in 1483, in the Polesine, while on diplomatic mission to Rovigo to assess the spoils acquired by the Venetian Republic after their victory over Ercole I d'Este, Duke of Ferrara in the War of Ferrara. (although in some accounts, the date of his death is sometimes given as early as 1477 and as late as 1488).
For historians of the Portuguese discoveries under Henry the Navigator, Alvise Cadamosto's accounts, the Navigazioni, have proven to be an invaluable document. Cadamosto's accounts, Gomes Eanes de Zurara's chronicle and the memoirs of Diogo Gomes, are practically all that remain of the contemporary written record of the Henrican discoveries. Indeed, until the publication of João de Barros's Decadas da Asia in 1552 (which drew on a manuscript draft of Zurara's chronicle), Cadamosto's Navigazioni was the only published work circulating in Europe about the Portuguese discoveries. Cadamosto emphasized the central role of Prince Henry, and was instrumental in building up the image of the Navigator Prince for posterity. Compared to the hagiographic Zurara and the fallible Gomes, historians have relished and lauded the reliability and detail provided by Cadamosto, giving a richer and clearer view of how the Henrican enterprise operated.
Cadamosto's accounts are also invaluable for historians of Africa, providing the first written detailed accounts of the Senegambia region, beyond the fringes touched one century earlier by Arab historian Ibn Battuta. Cadamosto gives a summary of contemporary European knowledge about West Africa. He describes the Mali Empire (Melli) and the Trans-Saharan trade, e.g. how Berber caravans carry the Saharan salt from desert pans like Teghaza (Tegazza) to frontier cities like Timbuctu (Tombutto).  He goes to explain how gold coming out of the heart of Mali goes out in three parts, one to Cochia (Kukiya) and then eastwards onto Egypt, the second via Timbuctu to Toet (Tuat) and then north towards Tunisia, and a third part, also via Timbuctu, goes west to Hoden (Ouadane), destined for Morocco, part of which is deviated to the Portuguese factory at Arguin.
Cadamosto is the first known person to refer to the Senegal River by its recognizably modern name (Rio di Senega) rather than the "western Nile". Curiously, Cadamosto notes that the Senegal was probably the Niger of ancient geographers (e.g. Ptolomey). He repeats the old error of assuming that the Senegal river and the (actual) Niger river are connected to each other, forming one great east-west river, and relates the legend that it was believed to be a tributary of the great Biblical river of Gihon (Gion) that flowed from the Garden of Eden across the lands of Aethiopia.
Cadamosto describes the Wolof (Gilofi) empire, which he notes was bound on the east by the Fula Tekrur/Toucouleur (Tuchusor) and to the south by the Mandinka states of the Gambia River (Gambra)  Cadamosto goes into quite some detail on the politics, society and culture of the Wolof states. He supplies a meticulously detailed eyewitness description of the Cayor village he stayed in 1455, the Damel's court, the people, customs, economy, local fauna and flora, etc. The details demonstrate Cadamosto's sheer curiosity – he describes the courtly customs, the houses, the use of cowrie shells as currency, the food and drink, the operation of local markets, livestock and cultivation, the production of palm wine, weapons, the dances and music, the reaction to European novelties (clothes, ships, cannon, bag-pipes). In all this, Cadamosto's narrative evinces a degree of honest curiosity and absence of prejudice perhaps surprising for a European of that era. Cadamosto attempts a similarly detailed account of the Mandinka people of the Gambia River, making particular note of their abundant cotton (rare in Wolof areas), although not nearly as complete, as he did not seem to venture much away from his boats there. He does not cease to marvel at the extraordinary wildlife which is far more plentiful around the Gambia, notably the hippopotamus (which he calls the "horse fish") and the largely unfamiliar African elephant (whose meat he was tempted to taste – a piece of which he salted and brought back to Portugal for Prince Henry himself; a preserved elephant's foot would be forwarded to Henry's sister, Isabella, Duchess of Burgundy.).
Alvise Cadamosto's accounts were first published in Italian at the head of the famous 1507 collection Paesi novamente retrovati, edited by Francazano Montalboddo and published in Vicenza. It was quickly followed by translations into Latin (1508), German (1508) and French (1515). The Italian version was reprinted in the famous Ramusio collection of 1550. Although reprinted and widely disseminated in other countries, a Portuguese translation did not appear until 1812.
Cadamosto was also long alleged to be the author of the Portolano del mare, a rutter with sailing directions for the Mediterranean Sea coasts, found in the library of St. Mark in Venice, with the publication stamp of Bernardo Rizzo in 1490. Cadamosto's authorship of the portolano has been generally discarded in modern times.
Editions of Cadamosto's Navigazioni:
Apocryphal (not Cadamosto, but attributed to him in the past):