One book. One widely-read and uncritically-accepted misinformation campaign. One monumental piece of revisionist history entitled History of the Warfare of Science with Theology in Christendom.
Cornell University was established in Ithaca, New York in 1865. It was arguably the first institution of higher learning founded as (what we would call today) a secular university. Prior to that time, the vast majority of--if not all--universities were founded on religious grounds. (Again, the majority were Christian or Jewish, with a small number of Islamic institutions.) So Cornell's co-founder and first president, Andrew Dickson White, apparently spent a good deal of his time and energy justifying the need for such a place. White's most famous literary work was this book, published in 1896. The problem is that its claims and conclusion are grossly inaccurate, the result of a combination of poor scholarship and myopic bias.
Despite its general departure from historical truth, White's thesis has been successfully transmitted (through those with a wish to believe it) all the way down to our generation, and some of its erroneus claims are still part of our education system's orthodoxy. Lest you think I'm making this up, I'll end this post with what Wikipedia has to say...
...White's book became an extremely influential text on the relationship between religion and science. The premise of the book—known as the conflict thesis—was very prevalent among historians through the 1960s. Since the 70s and 80s, many historians of science have reevaluated the history of science and religion, finding little evidence for White's claims of widespread conflict; instead, they often blame White for perpetuating a number of scientific myths, such as the idea that Christopher Columbus had to overcome widespread belief in a flat earth.