T and O map

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]

A later manuscript added the names of Noah's sons (Sem, Iafeth and Cham) for each of the three continents (see Biblical terminology for race).^[1] A later variation with more detail is the Beatus map drawn by Beatus of Liébana, an 8th-century Spanish monk, in the prologue to his Commentary on the Apocalypse.

^ ^a ^b Williams 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."

[Williams13-1] Williams 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."

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