In this work he had no superior in his day. While this Jewish scholar helped the Portuguese to many notable achievements in their daring voyages, another one, at a later period, was almost the direct cause of their being overtaken by the Spaniards in the race for new discoveries. For it was Joseph Vecinho, physician to King João, of Portugal, considered by the high court functionaries to be the greatest authority in nautical matters, who influenced the King to reject the plan submitted by Christopher Columbus (1446?‒1506), and thereby caused the latter to leave Portugal for Spain in 1484. Columbus came to Spain when Ferdinand and Isabella, with the aid of the newly introduced Inquisition, were despoiling the wealthy Marranos, who were burned at the stake in large numbers. The last war with the Moors had already begun. Another and more famous Jewish scholar was to make amends for whatever suffering was caused to the great discoverer by Vecincho’s fatal advice. Abraham Ben Samuel Zacuto, who was born in Salamanca, Spain, about the middle of the 15th century and died an exile in Turkey after 1510, was famous as an astronomer and mathematician, and in his capacity as one of the leading professors in the university of his native city was formerly the teacher of the above named Vecinho. He was more discerning than his pupil, and when he learned to know Columbus, soon after the latter’s arrival in Spain, he encouraged him personally and also gave him his almanacs and astronomical tables, which were a great help in the voyage of discovery. Zacuto was among the first influential men in Spain to favor the plans of Columbus, and his favorable report caused Ferdinand and Isabella to take him into their service in 1487. The explorer was then ordered to proceed to Malaga, which was captured several weeks before, and there made the acquaintance of the two most prominent Jews of Spain in that time――the chief farmer of taxes, Abraham Senior, and Don Isaac Abravanel. These two men were provisioning the Spanish armies which operated against the Moors, and were in high favor at Court. Abravanel was one of the first to render financial assistance to Columbus.