"The Greatest Memorial of Medieval Cartography"

About 1450 Venetian monk Fra Mauro completed the Fra Mauro map, a circular planisphere drawn on parchment and set in a wooden frame, about two meters in diameter. The map was discovered in the monastery of San Michel in Isola, Murano, where the Camaldolese cartographer had his studio. It is preserved in the Biblioteca Nazionale Marciana in Venice.

"The Fra Mauro map is unusual, but typical of Fra Mauro's portolan charts, in that its orientation is with the south at the top, one of the usual conventions of Muslim maps, in contrast with the Ptolemy map which has the north at the top.

"Fra Mauro was aware of the Ptolemy map, and commented that it was insufficient for many parts of the world:

"I do not think it derogatory to Ptolemy if I do not follow his Cosmografia, because, to have observed his meridians or parallels or degrees, it would be necessary in respect to the setting out of the known parts of this circumference, to leave out many provinces not mentioned by Ptolemy. But principally in latitude, that is from south to north, he has much 'terra incognita', because in his time it was unknown." (Text from Fra Mauro map)

"He recognized however the extent of the East given by Ptolemy, thereby suppressing the central position that Jerusalem had held on previous maps:

"Jerusalem is indeed the center of the inhabited world latitudinally, though longitudinally it is somewhat to the west, but since the western portion is more thickly populated by reason of Europe, therefore Jerusalem is also the center longitudinally if we regard not empty space but the density of population." (Text from Fra Mauro map)

"Fra Mauro regarded the world as a sphere, although he used the convention of describing the continents surrounded by water within the shape of a disc, but had no certainty about the size of the Earth:

"Likewise I have found various opinions regarding this circumference, but it is not possible to verify them. It is said to be 22,500 or 24,000 miglia or more, or less according to various considerations and opinions, but they are not of much authenticity, since they have not been tested." (Text from Fra Mauro map)

"The depiction of inhabited places and mountains, the map's chorography, is also an important feature. Castles and cities are identified by pictorial glyphs representing turreted castles or walled towns, distinguished in order of their importance."

"Fra Mauro also probably relied on Arab sources. This is suggested by the North-South inversion of the map, an Arab tradition examplified by the 12th century maps of Muhammad al-Idrisi, and the detailed information on the southeastern coast of Africa, which was brought by an Ethiopian embassy to Rome in the 1430s" (Wikipedia article on Fra Mauro map, accessed 01-12-2009).

A critical edition of the map was published by Piero Falchetta in 2006.