A T and O map or O–T or T–O map (orbis terrarum, orb or circle of the lands; with the letter T inside an O), also known as an Isidoran map, is a type of
early world map that represents world geography as first described by the 7th-century scholar
Isidore of Seville (c. 560–636) in his De Natura Rerum and later his Etymologiae (c. 625)[1]
So the earth may be divided into three sides (trifarie), of which one part is
Europe, another
Asia, and the third is called
Africa. Europe is divided from Africa by a sea from the end of the
ocean and the
Pillars of Hercules. And Asia is divided from
Libya with
Egypt by the
Nile... Moreover, Asia – as the most blessed
Augustine said – runs from the southeast to the north ... Thus we see the earth is divided into two to comprise, on the one hand, Europe and Africa, and on the other only Asia.[2]
Etymologiae, chapter 14, de terra et partibus:
Latin: Orbis a rotunditate circuli dictus, quia sicut rota est [...] Undique enim
Oceanus circumfluens eius in circulo ambit fines. Divisus est autem trifarie: e quibus una pars Asia, altera Europa, tertia Africa nuncupatur.
Etymologiae, chapter 14, de terra et partibus (translation):
The [inhabited] mass of solid land is called round after the roundness of a circle, because it is like a wheel [...] Because of this, the
Ocean flowing around it is contained in a circular limit, and it is divided in three parts, one part being called Asia, the second Europe, and the third Africa.[3]
History and description
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.[4][5] 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,[6] 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.[6][7]
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.
Jerusalem was generally represented in the center of the map as the navel of the world, the umbilicus mundi. Asia was typically the size of the other two continents combined.[citation needed]
Because the Sun rose in the east, Paradise (the Garden of Eden) was generally depicted as being in Asia, and Asia was situated at the top portion of the map.[citation needed]
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. The four sacred rivers of the
Holy Land were always present.[dubious –
discuss][citation needed]
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.[citation needed]
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.[citation needed]
Unknown, Mer des hystoires world map, 1491, following the model of the T-O map, centered on Jerusalem with East (the biblical location of Paradise) at the top.
On the left part of the sheet is a zonal or climatic map, communicating geographical information. On the right is a "T-O" map. By
Jacobus Philippus Bergomensis.
T and O map accompanied by a
V-in-square map, from a copy of the Etymologiae (
c. late 8th century).
^
abWilliams 1997, p. 13: "...the Isidoran tradition as it was known from peninsular examples, including the earliest of the ubiquitous T-O maps. This emblematic figure appears twice at the foot of folio 24v in a copy of Isidore's De Natura Rerum, now Escorial R.II.18... The relevant text comes from the concluding passage of the De Natura Rerum, Chapter XLVIII, 2... When, in the ninth century, the Escorial manuscript fell into the hands of Eulogius and was supplemented, this precise text (Etymologiae XIV, 2, 3) was placed on the page, folio 25r, facing the primitive map and was introduced another small T-O map. To this later T-O diagram, however, were added the names of Noah's sons- Shem, Japheth and Ham, for Asia, Europe and Africa, respectively-outside the circle of the globe. This apportionment is only implicit in the Bible (Genesis 9: 18-19). Josephus (d. c.100 AD) is more explicit as was Hippolytus of Rome, whose chronicle of 234 in its Latin translation disseminated the Noachid distribution in the West. Isidore's Etymologiae, however, the distribution of Noah's sons is not highlighted, but only incidentally reported with the description of the location of cities in Book IX. It seems clear, if we accept the evidence of Escorial R.II.18, that the Shem-Japheth-Ham distribution was not in the primitive Isidoran diagram. This means that Isidore's use of the T-O diagram was not informed by any overt religious content."
Christoph Mauntel, Die Erdteile in der Weltordnung des Mittelalters. Asien – Europa – Afrika (Monographien zur Geschichte des Mittelalters 71), Hiersemann, Stuttgart 2023.
Christoph Mauntel, ‘The T-O Diagram and its Religious Connotations – a Circumstantial Case’, in Christoph Mauntel (ed.), Geography and Religious Knowledge in the Medieval World, Berlin/Boston, deGruyter, 2021, pp. 57-82.
ISBN9783110685954
Carlo Zaccagnini, ‘Maps of the World’, in Giovanni B. Lanfranchi et al., Leggo! Studies Presented to Frederick Mario Fales on the occasion of his 65th birthday, Wiesbaden, Harrassowitz Verlag, 2012, pp. 865–874.
ISBN9783447066594