The following summarizes our findings related to historical thinking on the shape of the Earth.  Much more detail and historical quotes can be found in Chapter 5 - "Analysis of 7000 Years of Thinking Regarding Earth's Shape".

As we mentioned before, there is plenty of evidence of flat earth thinking in very ancient times.  Examples include:  Sumerian civilization (5000 BCE); Babylonian civilization (4500-500 BCE); Abraham (2100 BCE); Thales of Miletus (640-545 BCE); Anaximander of Miletus (611-547 BCE); Anaximenes of Miletus (525 BCE); Anaxagoras of Klazomenae (497-428 BCE); and Leukippos of Abdera (450-420 BCE).  During these times, a widespread acceptance of flat earth thinking does not appear to be in dispute.

Next, we find a period of great advances in understanding the earth's true shape and dimensions in the works of both scientists and theologians.   This began in ancient Greek times.  Examples of spherical earth thinking (some with dates overlapping above flat earth thinking) include: Pythagoras (582-500 BCE); Aristotle (384-322 BCE); Aristarchus (310-230 BCE); Eratosthenes (276-196 BCE); Hipparchus of Nicaea (165-127 BCE), Pliny the Elder (50 CE); and Ptolemy (90-168 CE).

However, there is some persistence of flat earth thinking during the pre-medieval times and beyond.  Examples include:  Lucretius (99-55 BCE); the Bible; Lactantius (245-325 CE); St. Cyril of Jerusalem (315-386 CE); St. John Chrysostom (344-408 CE); Severian, Bishop of Gabala (408 CE); Orosius (385-420 CE); Diodorus of Tarsus (394 CE); and Cosmas Indicopleustes (547 CE).

But, look at where we are: 547 CE, just barely setting foot inside early medieval times with a single verifiable proof of flat earth thinking. Where does this leave the argument that medieval people believed the earth to be flat and were scared of sailing of its edge?!

Then, as we proceed into the medieval age, there's abundant evidence of spherical earth thinking.  Examples include: St. Isidore of Seville (560-636 CE); the Venerable Bede (673-735 CE); St. Virgil of Salzburg (Vergilius), Bishop (745-784 CE).  From here, there is an unending list spherical earth belief represented in the historical record.

It is interesting to note that some of the early spherical proponents during this time were cautious with their views, likely due to fear of repercussions from the Church.  Some would simply refer to the ancient Greek teachings, quoting 'the philosophers' as teaching this or that, though without finding fault with them.  Others would entirely sidestep the issue by saying we have no reason to ponder such thoughts because all we need to know is in the Bible.  Examples of these two cautious approaches include: Saint Basil, Bishop of Caesarea (329-379 CE); St. Augustine (354-430 CE); and St. Isidore of Seville (560-636 CE).

In our view, the Venerable Bede (673-735 CE) represents a major turning point.  He not only wrote of a spherical earth, but he did so without the cautious approach described above.  This seems to indicate that a spherical view is widely held AND that the Church is not concerned about a scriptural conflict.  Bede is also a major turning point because medieval writers who followed him quoted him frequently.

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As we mentioned before, we cannot say precisely that, "At time X, people no longer believed the earth was flat."  We cannot even say that "The Church believed..." without being clear about which Church is in question and who precisely in that Church.  Even today there are a tiny few who still believe the earth is flat, as crazy as this is, so it's true that we can't say, at a distance of 1000 or 500 years, that no one in 500 AD or 1500 A.D. believed the earth was flat.  However, an important point using reason is that we do NOT find numerous strident defenses of the idea of a round earth being presented in the face of theological or scientific opposition.  We may be able to deduce from this that it was not really even a 'hot topic'.  This lends credence to the argument that it was probably a minority position and a relatively minor controversy.
 

The references to a spherical earth are so abundant after Bede's time
that we have not bothered to summarize them here.   Instead, refer to
Chapter 5 - "Analysis of 7000 Years of Thinking Regarding Earth's Shape".

 
For additional references on the scientific advances made during Medieval times and the view of a spherical earth, refer to our quotes section in Chapter 5.  Also refer to "Planets, Stars, and Orbs: The Medieval Cosmos, 1200-1687", by Edward Grant [92] and to "Heaven and earth in the Middle Ages: the physical world before Columbus", by Rudolf Simek. [93] Simek has listed a small number of texts which indicate that Old Norse audiences of the thirteenth century, at least in ecclesiastical and courtly circles, were familiar with the belief that the earth is spherical. This idea had been an integral part of scholarly learning in Europe since the eighth century, and from the twelfth century it was being taught to most clerics; by the thirteenth century it had found its way into popular literature. [93]