The Battle of the Teutoburg Forest took place in 9 AD, where an alliance of Germanic tribes ambushed three Roman legions led by General Publius Quinctilius Varus. This battle marked a significant turning point in the Roman Empire's expansion into Germania, as the Germanic forces successfully used their knowledge of the dense forest terrain to their advantage. The defeat resulted in the loss of approximately 20,000 Roman soldiers and halted Roman advances into the region. The battle is often seen as a pivotal moment in Roman history, leading to a more defensive stance along the Rhine River and shaping the future of Roman-Germanic relations.