It is probable enough that he was acquainted with some of the pre-scientific or "theoretical" designs, such as those of the "Beatus" type from the eighth and subsequent centuries; those which are to be found illustrating manuscripts of Sallust, Higden, Matthew Paris, St. Jerome, or Macrobius' Commentary on the "Dream of Scipio;" and those of Arabic geographers like Edrisi[260]--to name only a few examples--but he can hardly have derived much assistance from them. The great thirteenth century wheel-map pictures--as, for instance, those we know as the Hereford or Ebstorf Mappemondes--expressed the very antithesis of his spirit; and the same must be said of the greater part of the Mediæval cartography before the appearance of the portolani. [Footnote 260: Twelfth century.] From certain books of travel, such as those of Carpini, Rubruquis, Odoric, Pegolotti, or Marco Polo, he may, however, have received great assistance. The merchants and missionaries who opened so much of Asia to the knowledge of Europe during the Crusading period, furnished the most direct stimulus for the discovery of a direct ocean route to the treasures of the East. And to find such a route by the circumnavigation of Africa was, as we have suggested before, one of the primary objects of the Infant's life and work. But, in addition to the Maps of his predecessors, the Infant was almost certainly acquainted with some of the chief cartographical works of his own time, falling within the period of his exploring activity, and we must finish this brief survey with some notice of these. Continuing the catalogue, we have (15) A map by Mecia de Viladestes of 1413. This is a Catalan portolano, signed "Mecia de Viladestes me fecit in ano 1413," and is noticeable as containing a reference to the voyage of Jayme Ferrer in 1346, similar to that on the great Catalan atlas of 1375.[261] [Footnote 261: A work by the same author, of 1457, is said to be at the Carthusian Monastery of Segorbe, near Valencia, but it is not yet fully identified, and is supposed by some to be the same as that just noticed.]