The Wikipedia flat-earth article quotes Severian thus:
The earth is flat and the sun does not pass under it in the night, but travels through the northern parts as if hidden by a wall.
A reference is given of “J.L.E. Dreyer, A History of Planetary Systems’, (1906)” which needs to be verified. A limited preview of it is here, and Severian is on p.211-2. (Update: the whole book is here). Here is what is said:
A contemporary of Basil, Cyril of Jerusalem, lays great stress on the necessity of accepting as real the supercelestial waters 1, while a younger contemporary of Basil, Severianus, Bishop of Gabala, speaks out even more strongly and in more detail in his Six Orations on the Creation of the World,2, in which the cosmical system sketched in the first chapter of Genesis is explained. On the first day God made the heaven, not the one we see, but the one above that, the whole forming a house of two storeys with a roof in the middle and the waters above that. As an angel is spirit without body, so the upper heaven is fire without matter, while the lower one is fire with matter, and only by the special arrangement of providence sends its light and heat down to us, instead of upwards as other fires do3. The lower heaven was made on the second day; it is crystalline, congealed water, intended to be able to resist the flame of sun and moon and the infinite number of stars, to be full of fire and yet not dissolve nor burn, for which reason there is water on the outside. This water will also come in handy on the last day, when it will be used for putting out the fire of the sun, moon and stars4. The heaven is not a sphere, but a tent or tabernacle; “it is He…that stretcheth out the heavens as a curtain and spreadeth them out as a tent to dwell in5“; the Scripture says that it has a top, which a sphere has not, and it is also written: “The sun was risen upon the earth when Lot came unto Zoar6.” The earth is flat and the sun does not pass under it in the night, but travels through the northern parts “as if hidden by a wall,” and he quotes: “The sun goeth down and hasteth to his place where he ariseth7.” When the sun goes more to the south, the days are shorter and we have winter, as the sun takes all the longer to perform his nightly journey1.
1 Catechesis, ix., Opera, Oxford, 1703, p. 116.
2 Joh. Chrysostomi Opera, ed. Montfaucon, t. vii. (Paris, 1724), p. 436 sqq. Compare also the extracts given by Kosmas, pp. 320-325.
3 I. 4.
4 II. 3-4.
5 Isaiah xl. 22.
6 Gen. xix. 23. The above is from the Revised Version, but Severianus (III. 4) has: “Sol egressus est super terram, et Lot ingressus est in Segor. Quare liquet, Scriptura teste, egressum esse Solem, non ascendisse.”
7 Eccles. i. 5.
1 III. 5.
Few of those familiar with Wikipedia will be surprised, then, to discover that the “quote” is in fact the words of Dreyer, not of Severian. Amusingly the “quote” has made its way, sans reference, into the French and German articles.
But the exciting part is that Dreyer clearly has read Severian, albeit in the Latin version, and so it should be possible to identify the material properly.
The French article tells us that a French translation exists of Severian’s six sermons on Genesis, plus one more. These are from Bareille’s 19th century translation of Chrysostom, and that in turn suggests that Bareille may have translated all of Chrysostom, if he was getting into the spuria as well.