Alvise Cadamosto or Alvise da Ca' da Mosto (, also known in Portuguese as Luís Cadamosto; c. 1432 – 18 July 1488) 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. 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. Background 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 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. Expeditions to Africa 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