The Battle in the Teutoburg Forest in September 9 CE was, for a long time, recognized as a major turning point in European history. The Romans lost three legions (XVIII, XIX, and probably XVII), and many scholars have argued that this made the Romans retreat to the western bank of the Rhine, leaving the territories in the east unconquered. As a result, Germany was born. There is a lot to be said against this. For example, archaeologists have always dated all Roman objects prior to 9, but are now realizing that there is evidence for continued Roman presence in Germany.
But that is not the common error I want to discuss today. I want to argue that the Teutoburg Forest was not a forest. Granted, the Roman historian Tacitus refers to a Saltus Teutoburgiensis (Annals, 1.60), but for centuries, no one knew where this was, until Renaissance scholars argued that it had to be somewhere near the Upper Weser, in a densely forested area. They found what they were looking for: the hills known as Osning, between modern Rheine and Detmold. In the nineteenth century, the Osning was renamed Teutoburg Forest. However, archaeologists have found the battlefield at a place called Kalkriese, north of Osnabrück. The ancient name was given to the wrong site.
But as I said, there was not a forest at all. Of course Tacitus’ saltus can mean “forest”, but it can also mean “narrows” (e.g. Livy 36.17, and Livy, Periochae, 22.8, 49.13, and 67.8.). This meaning better fits the situation, as the Kalkriese site is indeed a narrow stretch of land between a hill and a great bog. The author of Tacitus’ source must have thought of this, and Tacitus must have misunderstood this information.
But from pollen research we know that there were no big trees, and the only ancient author who refers to them is Cassius Dio, who is well-known for the way he adds details to his stories to give them some local color. Those barbarians on the edges of the earth, in his view, ought to live in an inaccessible country, full of mountains and forests. Naive faith in our sources has seriously impeded research – and perhaps we’re lucky because of that, because now, Kalkriese was found by professional archaeologists, and not looted in the eighteenth century by antiquarians.