The Jew of Barcelona who has navigated the whole known world―― Judah Cresques, “the Map Jew,” as director of the Academy of Navigation which was founded by Prince Henry the Navigator――One Jewish astronomer advises the King of Portugal to reject the plans of Columbus――Zacuto as one of the first influential men in Spain to encourage the discoverer of the New World―― Abravanel, Senior and the Marranos Santangel and Sanchez who assisted Columbus――The voyage of discovery begun a day after the expulsion of the Jews from Spain――Luis de Torres and other Jews who went with Columbus――America discovered on “Hosannah Rabbah”――The Indians as the Lost Ten Tribes of Israel――Money taken from the Jews to defray the expenditure of the second voyage of Columbus――Vasco da Gama and the Jew Gaspar――Scrolls of the Thorah from Portugal sold in Cochin――Alphonse d’Albuquerque’s interpreter who returned to Judaism. In the days when Church and State were one and indissoluble, and when all large national enterprises, such as wars or the search for new dominions by means of discovery, were undertaken avowedly in the name and for the glory of the Catholic religion, it could not have been expected that governments will make an effort to protect international trade as long as it was in Jewish hands. We must therefore go as far back as to the first half of the 14th century to find a record of Jews who went to sea on their own account in an independent way. According to the great authority on the subject of this chapter (Dr. M. Kayserling, “Christopher Columbus and the participation of the Jews in the Spanish and Portuguese Discoveries,” English translation by the late Prof. Charles Gross of Harvard University) Jaime III., the last king of Mallorca, testified in 1334 that Juceff Faquin, a Jew of Barcelona, “has navigated the whole then known world.” About a century later we find again a Jew prominently identified with navigation; but in this instance he is a scientific teacher, in the employ of an energetic prince who considered navigation as a national project of the greatest moment. Prince Henry the Navigator of Portugal (1394–1460), who helped his father to capture Ceuta, in North Africa, and there “obtained information from Jewish travellers concerning the south coast of Guinea and the interior of Africa”, established a naval academy or school of navigation at the Villa do Iffante or Sagres, a seaport town which he caused to be built. He appointed as its director Mestre Jaime of Mallorca whose real name was Jafuda (Judah) Cresques, the son of Abraham Cresques of Palma, the capital of Mallorca. Jafuda was known as “the Map Jew,” and a map which he prepared for King Juan I. of Aragon and was presented by the latter to the King of France, is preserved in the National Library of Paris.[2] He became the teacher of the Portuguese in the art of navigation as well as in the manufacture of nautical instruments and maps.