[239] See d'Avezac, Bolletino d. Soc. Geog. Ital., 1874, p. 408; Nordenskjöld, Periplus, 16 A.
[240] See d'Avezac, Coup d'œil historique sur la projection des Cartes de Geographie (1863), p. 38.
[241] Reproduced in part at the end of this edition of Azurara, vol. i, Plate 4.
[242] Thus Nordenskjöld sums up after an exhaustive review of all the chief early portolans: "Not only are the coast-legends the same, even the ... names in red ink of places considered of special importance to navigators were not essentially different in the three centuries from Vesconte to Voltius. Moreover: (1) The Mediterranean and Black Sea have exactly the same shape on all these maps; (2) a distance-scale, with the same unit of length, such as otherwise is used only on the Spanish and French Mediterranean coasts, occurs on all these maps, independently of the land of their origin; (3) the distances across the Mediterranean and Black Sea, measured with this scale, agree perfectly on the different maps; (4) the conventional shape given to many islands and capes remain almost unaltered on portolanos from the fourteenth to the sixteenth century. So that it may be thought proved that all these portolanos are only amended codices of the same original" (Periplus, 45 a).
[243] E.g., Nordenskjöld, in his last work (Periplus, 46, 47).
[244] Nordenskjöld conjectures probably between 1266 and 1300.
[245] Cf. (1) the Beatus maps of "St. Sever," "Ashburnham," "Turin," "London," of 1109, "Valladolid," "Madrid," etc., of the tenth, eleventh, and twelfth centuries; (2) the Hereford Mappemonde of the late thirteenth century, with which may be compared the Ebstorf world-map of c. 1300; see Konrad Miller, Die ältesten Weltkarten, Heft v, 1896.
[246] Signed "Johannes presbyter, rector Sancti Marci de Porta Janue me fecit." A priest answering to this description flourished in Genoa, 1306-1344; this may have been a younger relative.
[247] No Atlantic islands exist on the Tammar Luxoro portolan.
[248] Konrad Kretschmer believes Sanudo's maps to have been draughted entirely or principally by Vesconte.