I have known about the flat earth error for some time but I have never actually read a book or even a scholarly article detailing where the myth started and how it entered our popular culture. Then I came across Inventing the Flat Earth by Dr. Russell, and I was impressed with how quickly he presented the argument and dealt with the issue. The book is a very short read (77 pages, not including end notes, 30 pages, "selected" bibliography, 7 pages, and an index) and can be finished in an afternoon (or over a few days if you only take it a few pages at a time). It covers the topic very well and gives you a good sense of how, and why, the flat earth error started. But because of its length, it is only good as a starting point if you want to get deeper into the subject. For those who only want to learn about the flat earth error and how it started then this is the book for you.
First, the book is about the flat earth error also referred to as the Myth of the Flat Earth, not to be confused with the error of the flat earth. Simply put, the flat earth error is the idea that people in the middle ages thought that the earth was flat and not spherical. As Dr. Russell demonstrates, ever since the Greeks proved the sphericity of the earth the scholarly consensus has been that the earth was spherical. There was some debate as to the size, whether or not there was land on the opposite side and whether or not that land was inhabited. But there was never any serious question as to whether or not the earth was a sphere.
Dr. Russell explains that the only opposition to Columbus was not from people who thought the earth was flat, but from other scholars who thought that the earth was bigger than Columbus calculated it to be (which it was). If Columbus's calculations were correct then it would have been possible to sail west from Europe to Asia using the boats they were building at the time. If he was wrong, then the distance would have been too great and they would not have been able to make the journey (alive). That was the only concern raised by scholars at the time. There were a few people in history that flat out stated (ha ha) that the earth was flat, but of the two theologians/scholars that get cited most often, one had his writings condemned for being heretical (for other reasons), and the other was never read nor cited all throughout the middle ages except by two different writers, who only cited him to point out in no uncertain terms that he was wrong about the earth being flat. Other than that those writings were not cited, noted, quoted, or even read until the 1800's when historians and scholars began citing them as evidence that "everyone" believed the earth was flat. Dr. Russell goes into more detail in his book.
Sometime in the 1800's a few different people thought that it would be great to cast Columbus as a great scientist fighting against the darkness of the illiterate and ignorant traditions of the past and say that he was trying to prove that the earth was round and not flat. Thus scholars cherry picked the writings of a few theologians from the middle ages and said, "Look! People used to think that the earth was flat, and they thought this until Columbus proved that it was round." Thus from about 1870 to 1920 there was virtually unanimous consensus among historians that people (theologians and scholars) in the middle ages thought the earth was flat. This lasted until people actually began reading what they wrote, and not reading what other historians thought about what they wrote. After this there was a shift in the scholarly world that recognized that people in the middle ages did not think that the earth was flat, but unfortunately that idea became so strongly embedded in our culture that even today it is still put into text books and taught in our schools as being true (I asked my cub scouts about it and they all repeated back to me the flat earth error, as told them by their teachers. I then told them that their teachers were wrong and I set them right.).
Dr. Russell speculates as to the motivation of the scholars who started this myth. There were some non-scholars who contributed to the myth, such as Washington Irving, but it was mostly spread by scholars who had ulterior motives. There were some who promoted the idea so that they had a basis to attack the Catholic Church ("Hey, look at what the crazy Church leaders used to believe. And I hear they wanted to burn Columbus at the stake for believing the earth was round!"). There were others who used it to attack religion in general, saying that the idea was a hold over from an antiquated era when people believed in silly things such as magic, and religion. But "we have moved past that we are now in a more enlightened era, dominated by Natural Philosophy". This of course was all strongly influenced by the ideas of Aususte Comte, who viewed history as a progression from less enlightened to more enlightened ways of thinking. With this as the basis, it made sense to assume that any opposition to Columbus was due to unenlightened thinking about the world, which meant that everyone else must have thought that the earth was flat. So strong where these ideas that the myth persisted and persists to this day.
Dr. Russell also talks about how there might be some confusion regarding some words, such as antipodeans, which he explains scholars in the middle ages used to refer to people that lived on the other side of the earth, and modern scholars interpret to mean literally, the other side of the earth. Thus medieval scholars debated the existence of antipodeans (meaning people living on the other side of the earth), and scholars in the 1800's interpreted that debate to mean that they were discussing the existence of the other side of the earth, and used that debate as proof that they thought the earth was flat.
I would recommend reading this book, and I think it should be required reading for all elementary education majors. My only complaint is that the all the notes in the book are in endnote format, which means they are all crammed into the end of the book, and it is hard to have to keep flipping to the back of the book to see if the note is something interesting (i.e. a break down of the Latin root of a word used, and how the meaning changed over time) or if it simply contained a list of additional books to read. So my only complaint is in the format, not the writing. Footnotes would have been better.