As a medievalist I have found myself often challenged by non-medievalists' misconception of medieval people as believing that the world was flat and square, and even that one dropped off its edge. This seems to me Renaissance/Enlightenment propaganda against the Middle Ages as the 'dark ages of superstition and ignorance'. But it is certainly not borne out in medieval texts or in medieval art. I borrow from John Donne's Renaissance poetry the title for this modern prose on medieval cosmology.

Great maps, as at Hereford, show the mappa mundi as round. Medieval art can show God creating the world as a globe. Medieval kings held orbs, signifying the roundness of the world, the cross at its top for Jerusalem. One particularly recalls the Coronation Portrait of Richard II in Westminster Abbey. Generally medieval maps are of their 'known world', arranged in the T of Asia, Europe and Africa. But an Icelandic map shows two sides of the globe, one, the T map, the other the boundless ocean in between which Christopher Columbus was to try to cross to reach India and China./1 Already in the fourteenth century John de Mandeville describes yearning to cross that vast ocean from Chinese shores in order that way to return to Europe and as having his voyages checked against a mappa mundi by the Pope in Rome./2 Medieval libraries (without which the Renaissance could not have taken place) of classical texts treasured in monasteries and cathedrals included the texts of Ptolemy. Further refinements were added to this knowledge by the Arabs' study of Greek texts. But already Cicero's Somnium Scipionis and Boethius' De consoltatione philosophiae, based on Ptolemy and Pythagoras, had stressed that vision of the earth as a round ball. Not to be actually seen until the astronauts first viewed it from space in our lifetime.

Spain particularly is cognisant of the globe. Egeria had been noted in a Spanish document dated from the seventh century to have traversed the whole orb with her pilgrimages made in the fourth century./3 The eleventh/twelfth century Creation Tapestry at Gerona reflects what one also sees in the Beatus Apocalypse manuscripts. A fourteenth-century Castiglian painting shows Christ, God the Son, with the T-map globe in his left hand perched on God the Father's shoulders whose own arm is looped through the circular cosmos and whose feet are upon an ocean filled with fish. Spain's monarchs, Ferdinand and Isabella, came to commission Columbus' Voyage that would bring about America's official discovery. But Dante Alighieri had already postulated, in the Purgatorio, the existence of this 'nuova terra'. As had the Icelandic discovery before him of Vinland.

Brunetto Latino, Dante Alighieri's teacher, clearly presented the world as round, in his Tesoretto when describing his meeting with Ptolemy.

[Folio 25 verso]
Ch'io credo pur tornare
La via ch'i m'era messo;
Ché ciò che m'è promesso
Di veder le sette arti
E altri molte parti,
Io le vo'pur vedere
E cercare e savere
. . .
[Folio 26]
COsì un dì di festa
Tornai a la foresta,
E tanto cavalcai
Che io mi ritrovai
Una diman per tempo
In sul monte d'elempo,
Di sopra in su la cima.
E qui lascio la rima
Per dire più chiaramente
Ciò ch'io vidi presente:
Ch'io vidi tutto'l mondo,
Sì com'elgli è ritondo,
E tutta terra e mare,
E'l fuoco sopra l'aire;
Ciò sono quattro elementi,
Che sono sostenimenti
Di tutte creature
Secondo lor nature./4

Brunetto Latino continued that education, but in French, in his Li Livres dou Tresor whose manuscripts are to be found throughout Latin Christendom and which often show in miniature and drawing the roundness of the earth./5 All of this became material for Dante Alighieri to use in his Commedia in which he articulates in detail the cosmos, the round earth at its centre and the carefully calculated movement of the seven planets about it and even the Southern Cross./6 The only difference between their cosmos and ours is their centring of it on the earth, rather than upon the sun. Thus the mathematics they had to use to compute the movements of the planets, which to them looped about in subtle ways, had to be far more complex than ours because based on that fallacy and needing to predict the placements of these 'wandering stars'.

Notes
1 See the maps from Joachim Lelewel, Géographie du Moyen Age (Brussels, 1852), 3 vols., reproduced in Julia Bolton Holloway, The Pilgrim and the Book: A Study of Dante, Langland and Chaucer (Berne: Peter Lang, 1992), p. 153.
2 Mandeville's Travels, ed. M.C. Seymour (London: Oxford University Press, 1968), p. 243. See also the Early English Text Society editions of his work.
3 Si tratta di uno scritto del VII secolo, una lettera che un monaco galiziano, Valerio del Bierzo, indirizza ai suoi confratelli, esortandoli a prendere come loro modello le straordinarie doti spirituali di una pellegrina che "intrepido corde immensum totius orbis arripuit iter" ("con intrepido cuore, intraprese un viaggio interminabile attraverso tutto il mondo") - dice Valerio, con evidente amplificazione retorica: Pasquale Smiraglia, Accademia dei Lincei, 'La Citta e il Libro II: Il manoscritto, la miniatura', http://www.florin.ms/ beth.html For another intrepid woman globe-trotter see Iceland's Guthrithyr, who visited both Vinland and Rome, http://www.umilta.net/egeria.html
4 Brunetto Latini, Il Tesoretto (Firenze: Le Lettere, 2000), facsimile of Laurentian Library Strozziano 146.
5 Brunetto Latini, Li Livres dou Tresor (Barcelona: M.Moleiro Editor, 2000), facsimile of St Petersburg National Library Fr. F.V.III,N° 4, 2 vols., fols. 7, 28v, 31v, 30v, 38v.
6 Barbara Reynolds, for her completion of Dorothy Sayers' translation of the Commedia, used M.A. Orr's study of Dante's astronomy, carried out by a Victorian woman in an astronomical observatory in India, which was in turn based on that of his teacher, Brunetto Latino. M.A. Orr's work reflects that of Mary Somerville, the brilliant, self-taught mathematician and astronomer, who proved the existence of the eighth and ninth planets, Neptune and Pluto, before their discovery, from the erratic movements of the other planets effected by their gravity.