Sebastian Cabot, b. 1483–86?, d. 1557, explorer in English and Spanish service; son of John Cabot. He may well have accompanied his father on the 1497 and 1498 voyages, and he was for many years given the credit for his father's achievements. In the 19th cent., scholars, finding discrepancies in the Sebastian stories, branded him an impostor and applied his accounts to the 1498 voyage of John Cabot. However, recent research indicates that the Sebastian narratives relate to a later voyage (1509) made in search of the Northwest Passage. He may have reached Hudson Bay. In 1512 he entered Spanish service and in 1518 became chief pilot. After the return of Magellan's ship Victoria, he sailed (1526) from Sanlúcar de Barrameda with the ostensible purpose of loading spices in the Moluccas. Instead he explored the Río de la Plata country, spending several years along the Paraguay, Plata, and Paraná rivers, but the hostility of the Native Americans and the scarcity of food forced him to leave the country. He returned to Spain in 1530, a distrusted and discredited man. In 1548 he reentered English service, and in 1553 he became governor of a joint-stock company (later the Muscovy Company) organized to seek a Northeast Passage and open trade with China. Under his instructions an expedition sailed the same year under Sir Hugh Willoughby, who was lost in midvoyage and was replaced by Richard Chancellor. The expedition reached the White Sea, and a commercial treaty was negotiated with Russia, breaking the monopoly of the Hanseatic League.
See C. R. Beazley, John and Sebastian Cabot: The Discovery of North America (1964); R. C. Howard, Bristol and the Cabots (1967); R. Biddle, A Memoir of Sebastian Cabot (repr. 1970); David Goodnough, John Cabot and Son (1979).