Spherical Earth concept Although Isidore taught in the
Etymologiae that the Earth was "round", his meaning was ambiguous and some writers think he referred to a disc-shaped Earth. However, other writings by Isidore make it clear that he considered the Earth to be
spherical. Indeed, the spherical Earth had been the prevailing scholarly assumption since at least
Aristotle, who had delineated a
frigid clime at the
poles, a
torrid clime near the
equator, and a habitable
temperate clime in between. The T and O map represents only half of the spherical Earth, presumably a convenient
projection of the known northern temperate region. It was believed that no one could cross the torrid equatorial clime and reach the unknown lands to the south, the
antipodes.
Boundaries, center and orientation The
T is the
Mediterranean, the
Nile, and the
Don (formerly called the Tanais) dividing the three
continents,
Asia,
Europe and
Africa, and the
O is the encircling
ocean. In line with Isidore's description, Asia is normally depicted as equal in size to Africa and Europe combined. The majority T-O maps are oriented to the east, though examples of north, south and westward orientation can also be found. The idea that
Jerusalem was generally represented in the center of the map as the navel of the world, the
umbilicus mundi, is a false generalisation from a relatively small number of very famous 13th-century
mappae mundi. The earliest T-O maps marked no particular geographic center and while some early
mappae mundi were specifically centered on classical sites like Delos or the Cyclades, most simply had the Mediterranean or Aegean Sea in the middle. It was only after the First Crusade that Jerusalem began to be represented as the center of the world on medieval maps, a trend which rose to prominence from the mid-12th century through the early-14th century, but was never universally observed. The location of Paradise (the Garden of Eden) in the east of Asia is based upon the
Septuagint translation of Genesis 2:8, which describes the garden of Eden being planted in the east. This is a longstanding feature of Christian textual geographies, and while not present on the earliest T-O maps, it is a prominent feature of many early
mappae mundi, especially the
Beatus maps. These depictions are often combined with a depiction of the four rivers of Paradise: the Tigris, Euphrates, Pishon and Gihon, the latter two of which were sometimes understood by medieval cartographers as the Ganges and Nile (or Geon) respectively. These were either depicted as flowing within/out from paradise and/or as four major rivers on the map.
Additional details This qualitative and conceptual type of medieval
cartography could yield extremely detailed maps in addition to simple representations. The earliest maps had only a few cities and the most important bodies of water noted. Different cartographic material, which represented more useful tools for the traveler, were the
itinerarium, which listed in order the names of towns between two points, and the
periplus that did the same for harbors and landmarks along a seacoast. Later maps of the T-and-O conceptual format featured many rivers and cities of
Eastern as well as
Western Europe, and other features encountered during the
Crusades. Decorative illustrations were also added in addition to the new geographic features. The most important cities would be represented by sketches of fortifications and towers in addition to their names, and the empty spaces would be filled with mythical creatures. ==Gallery==