This paper examines the battle of Teutoburg (9 A.D.), its consequences on the Roman world, and the role cultural misunderstanding played on the tactical, operational, and strategic levels. The Roman commander's cultural misunderstanding of his enemy caused mistakes at the operational and tactical levels, while the Roman Emperor's cultural misunderstanding brought about mistakes at the strategic level and created poor policy decisions following the battle, which affected Rome like no other battle in its history. Chapter 2 examines the consequences of other Roman loses (with much higher casualties) to show how none of them carried the same impact as the Teutoburg loss. They were but temporary "setbacks", while Teutoburg was Rome's first military "defeat" in its history. The Roman direction of conquest into Germania and the image of the pre-Teutoburg Germanic barbarian (an image which changes greatly into an elevated status following the massacre) are also examined. Chapter 3 examines the commanders of both sides and the battle itself. Chapter 4 looks at the significance of this loss. This battle caused Rome to adopt its first permanent defensive boundary and set the first limit of the Roman Empire.