CathInfo.com

I am completely convinced of a stationary earth and Geocentrism, and open to but not really convinced of flat earth yet. What are some Saints, and quotes from them, showing they believed in a flat earth, and ideally why.

Basil, Hexaemeron: “Those who have written about the nature of the universe have discussed at length the shape of the earth. If it be spherical or cylindrical, if it resemble a disc and is equally rounded in all parts, or if it has the forth of a winnowing basket and is hollow in the middle; all these conjectures have been suggested by cosmographers, each one upsetting that of his predecessor. It will not lead me to give less importance to the creation of the universe, that the servant of God, Moses, is silent as to shapes; he has not said that the earth is a hundred and eighty thousand furlongs in circuмference; he has not measured into what extent of air its shadow projects itself whilst the sun revolves around it, nor stated how this shadow, casting itself upon the moon, produces eclipses. He has passed over in silence, as useless, all that is unimportant for us. Shall I then prefer foolish wisdom to the oracles of the Holy Spirit? Shall I not rather exalt Him who, not wishing to fill our minds with these vanities, has regulated all the economy of Scripture in view of the edification and the making perfect of our souls? It is this which those seem to me not to have understood, who, giving themselves up to the distorted meaning of allegory, have undertaken to give a majesty of their own invention to Scripture. It is to believe themselves wiser than the Holy Spirit, and to bring forth their own ideas under a pretext of exegesis. Let us hear Scripture as it has been written.”

Obviously, Basil's point is being missed here, since the shape of the earth does matter.  Just not in the context in which he's speaking.  We can be sure that at least one of the popular models is false.

Flat earth can and should be discussed in light of earlier Christians teachings and beliefs in order to get to the truth of the matter.  Dismissing the possibility of a flat earth by making heliocentrism and the globe earth a forgone conclusion is neither scientific nor spiritual.