[Footnote 237: Viz., before the end of the thirteenth century; see _Dawn of Modern Geography_, ch. vi, on "Geographical Theory in the Earlier Middle Ages," and especially pp. 273-284, 327-340, 375-391.] Strictly scientific map-making begins with the Mediterranean portolani. The earliest existing specimen of these is of about 1300, but the type then formed[238] must have been for some time in process of elaboration; and it is even probable that a fully-developed example from the middle of the thirteenth century may yet be discovered. [Footnote 238: _E.g._, in the Carte Pisane and the work of Giovann de Carignano.] "A sea-chart--probably a portolano--is mentioned as early as the account of the Crusade of St. Louis, in 1270."[239] So in Raymond Lulli's _Arbor Scientiæ_, written about 1300, we have reference to compass, chart and needle, as necessary for sailors.[240] Once again, it is probable that Andrea Bianco's planisphere of 1436[241] is only a re-edition of a thirteenth-century work, when the "Normal Portolano" was just in process of making, but had not reached even the comparative perfection of the Carte Pisane, Carignano, or Vesconte examples. [Footnote 239: See d'Avezac, _Bolletino d. Soc. Geog. Ital._, 1874, p. 408; Nordenskjöld, _Periplus_, 16 A.] [Footnote 240: See d'Avezac, _Coup d'œil historique sur la projection des Cartes de Geographie_ (1863), p. 38.] [Footnote 241: Reproduced in part at the end of this edition of _Azurara_, vol. i, Plate 4.] The earliest dated portolan is that of 1311, by Petrus Vesconte; and from this time the maps of this class, whose central feature is an accurate Mediterranean coast-line, increase rapidly, being indeed all reproductions of one type,[242] occasionally introducing additions or corrections, especially in outlying parts, but not often varying much from one another in the central portions. The type is reasonably believed by some[243] to have originated among the Catalans, either of Spain, France, or the Balearic Isles, well within the thirteenth century.[244] In connection with this, we may recall the point mentioned by Barros, that Prince Henry the Navigator obtained the services of Master Jacome, or James, from Majorca to instruct the Portuguese captains in navigation, map-making, and the proper handling of nautical instruments.