With the departure of Arminius from Varus and the legions, Varus proceeded on track going north of the normal Roman routes used during the summer campaigns; this placed the Romans in unfamiliar territory. Confidently Varus marched on, still believing that Germania had been pacified and this was nothing more than a minor rebellion; as with many other Roman commanders they believed in using a show of force to give the locals second thoughts in rebellion; there is little doubt Varus believed this is what he was doing by taking a more northern route.

The standard practice for the Roman army when campaigning outside the Empire was to place auxiliaries and cavalry in the front and rear of the marching column. Working towards the center from both ends would be the legions and then the baggage train and the commander with his staff were in the center of the column, thus giving them the most protection from a possible attack from the front or rear of the column. This practice works well when in open countryside or on roads, but it is rather difficult to maintain in a forest and mountain region. Depending on the number of soldiers in the column, the column could be anywhere from four to nine men wide. With an average of a yard between each man and if the column was only six men wide, the column would have been almost two and a quarter miles long with Varus's 18,000 men, with an average speed of approximately three miles per hour. No one can say with any certainty the size and speed of Varus's column; however, based on what is known on Roman formations and marching it is a very good guess.

Having campaigned all summer, it is likely the soldiers were growing weary and looked forward to the more relaxing winter encampments along the Rhine. This weariness may have contributed greatly to not observing their surroundings for signs of ambushes. As the terrain of open fields changed to forests and swamps, the Romans no doubt felt apprehension as the terrain closed in around them. Playing into this fear were the beliefs of many of the soldiers that the forests and marshes were inhabited by spirits who preyed upon people crossing their lands. Therefore, since these soldiers were still pagan they wore charms and said prayers to their gods and goddesses asking for protection from the spirits. It was in similar lands that Drusus and his legions nearly met  their end, a memory that likely also played on the minds of Varus's solders as the event had occurred in their recent history. Varus's being present within the column did give some confidence to the soldiers because he was the acting Governor of Gaul and Germania and that gave an added sense of security.

The track was becoming more and more difficult for Varus; his soldiers now were having to cut trees to allow the passage of the baggage wagons and fill in large mud holes to prevent the baggage wagons from getting stuck. As the terrain became more and more a forest, the Romans did pass by settlements of farm houses, but found them to be abandoned; the farms had fields of wheat and barley and they could clearly see that cows had recently pastured on some of the fields. Both the inhabitants and the cows were absent from all the farms the Romans encountered. It could have been the noise of the marching column that frightened them, or in retrospect it could have been the first signs of an ambush as the locals were likely at the ambush site.

Cassius Dio, a Greek historian, tells how at the moment the Romans entered the passage to Kalkrieser Berg a great storm came up as if the Germanic people had called upon their gods to defend them; adding further hardship to the Romans, they now became disoriented, separated into smaller groups, constantly slipping and falling in the mud due to the heavy armour they wore, and the fear of the wilds of Germania grew deeper. As the column entered the narrows between the steep banks with thick forest on one side and a great bog on the other, the Romans found themselves confined to a passage hardly half a mile wide and four miles long. Wide muddy streams from the heavy rains of the storm now cut the path up into sections and pools and swampy areas made the passage treacherous. Eventually the Romans made it to a sandy strip of land that provided some secure footing; it measured about 100 yards wide. Moving the baggage wagons over this terrain was now nearly impossible.

As the Romans entered an even narrower part of the passage with the forest to the immediate left and willow and alder to the right before the land fell off to the bog, the conditions were now right for Arminius to spring the trap. Several volleys of spears from both sides rained down on the unsuspecting Roman column; the screams from the front of the column could barely be heard as the column pushed forward, unable to stop and prepare itself.

Due to the marching formation the Romans found themselves in due to the terrain, they were not able to quickly make the transformation into a fighting formation, and to make matters worse for the Romans they were not accustomed to fighting in a forest and swamp environment. The spear attacks continued for several minutes and the dead piled up in the narrow passage, making the Roman soldiers trip over the bodies and slip in the blood-soaked mud. There was nowhere for the Romans to retreat to; all they could do was come to a halt and be cut down or keep going forward and be cut down. Then as suddenly as the spear volleys had started they ended, but this was not the end of the attack. From the forest the Germanic warriors swooped down on the Romans with their swords, cutting down more Romans. This threw the Roman column into complete chaos, as now thousands of dead Romans littered the path way.

It is not known exactly how many Germanic warriors were at the Battle of Teutoburg Forest; it is estimated there were at least 18,000; given Arminius's experience in the Roman army it is likely he would have put an even distribution of veterans among the younger men who had never engaged in battle before in order to be able to control the lines and volleys. Generally there would have been in a line two men deep behind the wall throwing spears. This allows for a spear to be thrown accurately every 4 seconds; as the first man throws he falls back to the second line to retrieve a spear to replace the man in the front line. It is thought that the scouts for the Roman army were in on the ambush plans, as it was customary to use local auxiliaries to scout the land as they knew it. If this was the case the scouts would have ridden ahead of the column to warn the waiting Germanic army of the approaching column, ridden back to the column and given the all clear to move ahead, then ridden ahead again to get out of the way of the initial volley of spears.

The Germanic warriors were not nearly so heavily armored as the Romans, thus allowing them to move quickly and unimpeded over the terrain. With long spears and long swords they were much better equipped for the terrain than the Romans with their heavy armour, short swords, and light javelins. Due to the narrow passage and thick mud, communication through the column was nearly impossible. The messengers on horseback could not get through the mass of soldiers quickly or efficiently enough for communications to be effective. Therefore, it took several minutes for word to reach Varus that he was even under attack, and when he did find out he believed it to be nothing more than a minor skirmish and ordered the column to push forward. Varus's orders essentially sealed the Romans' fates; when the rear marched forward at an increased rate the column crashed into the battle as the front was stationary, the rear of the column slammed into the front crushing the center. Some of the Roman soldiers in the center and rear of the column did mount a retreat, but most were captured or killed. Some managed to successfully retreat by hiding during the day and moving very cautiously at night, making their way back to Xanten, where the news of the ambush had by then arrived. At the end of the first day what remained of the Roman column quickly made camp, destroying the baggage wagons and any supplies they did not need so they would not fall into the hands of the Germanic tribes.

There is some debate as to whether there was a night raid on the Roman encampment as the Germanic tribes certainly had the skill and knowledge necessary. Having the Romans pinned down and beaten, it would have made strategic sense to press the attack into the night to keep the Romans on edge and even more tired for the next day of battle. With the Harii a night raid against the Romans would have been easy, for they preferred night attacks. It is also likely a guard patrol was set up to defend German positions on the wall from any Roman night attack, which were rare but did happen. The Harii likely conducted night warfare even if it was killing off stragglers in the forest. This way the other tribes could rest and prepare for the next day of battle, a luxury the Romans probably did not have. One has to also consider that in battle, the Germanic encampment was likely a mile or two from the actual wall, thus they could be sure that a Roman attack on the encampment would not happen. This is of course just theory and practical battle tactics; it does not imply in any way that this is what happened.

The second day of battle was pretty much a repeat of the first day, with the Romans trying to take the wall and forest only to be repelled with heavy losses. There is practically no information about the second night, if the Roman encampment was attacked or if they even made it back to their camp. By the third day the Roman numbers were so few that Varus, seeing the battle was now over, fell on his sword to avoid being taken hostage. He died in disgrace; following suit, his generals and officers also killed themselves to avoid capture. Upon hearing of the death of Varus and the officers, what remained of the legionaries fought hard, likely to try and retreat, but were overwhelmed by the Germanic army and either captured or killed. The Roman army had suffered a crushing defeat: thousands of Romans lay dead and dying while only a few hundred of the Germanic warriors had been killed or mortally wounded.

Here is a very well done video by Princepsmaximus, YouTube on the actual events that led up to the battle, the battle and the outcome.

Battlefield Trauma

In the modern age battlefield trauma is often dealt with quickly. The modern military has a trained medical corps that in most cases are able to deal with various traumas suffered by soldiers. In 9 CE the Roman army did have advanced battlefield medicine for the time period; however, at the Battle of Teutoburg Forest getting soldiers back to an area for treatment was practically impossible. Even if treatment had been given at night to the soldiers the medical people could get to, the types of wounds they would have received from the Germanic army would have resulted in death either by destruction of vital organs, shock, or loss of blood, and generally all three of these would have occurred. During the initial spear volleys a large number of the legionaries would received neck, throat and chest wounds. Following the spear volley the next onslaught of spears and swords would have delivered more quick deaths with additional chest wounds and neck wounds from swords would have brought death instantly. However, the removal of limbs like arms and even possibly a leg would not have resulted in instant death but a death by bleeding out, which can be as much as 10 minutes to 30 minutes of agony depending on the wound.

The doctor Japyx heals Aeneas, wounded in the leg (flanked by his mother, the goddess Venus, and by his own son Anchises, who is weeping). Ancient Roman fresco from the "Surgeon's House" in Pompeii, Italy, mid-1st century CE.

Punctures to the intestines and stomach region would result in an extremely painful and slow death. Battle shock was another  killer; the initial attack of the spear volley and the immediate chaos that followed caused many to collapse unconscious, resulting in them being trampled, drowned, or later killed by the Germanic warriors who went over the battlefield killing many survivors. The most common cause of death was loss of blood and is linked to the the other causes of death by internal organ destruction and shock. Another contributing cause to the death of Roman soldiers was broken bones, which were common from sword and axe blows. With one or more broken bones the Roman soldier was unable to defend himself or escape the onslaught of the attack. In the battle conditions that existed at Teutoburg Forest, the barrage of projectiles, stabbing and slashing, there would have been no way for a wounded soldier to tend to the wound. Romans who survived the initial attack of day one and did not make it back to the encampment likely died in the first night from exposure, the fourth cause of death.

Germanic deaths were caused by lacerations and punctures they received when attacking the Roman column from the Roman short sword, called a gladius. Unlike the Roman soldiers, the Germanic warriors had a chance to receive medical treatment on the battlefield; due to the high interaction between the Germanic tribes and the Roman Empire, the Germanic tribesmen had learned battlefield medicine and surgical practices while serving as auxiliaries in the Roman army. Because the Roman military medical system was based on Greek medicine, it was the most advanced medical treatment and care in its time. As an example to how advanced Roman military medicine was, the medical corps that travelled with the army had a device that could remove an arrowhead without tearing or further damaging tissue and muscle. They also developed a medical clamp to help prevent gangrene; however, the most advanced treatments relating to battlefield trauma were given at the legionaries' bases like Xanten. Another killer of Germanic wounded would have been infection from deep punctures; the warrior may have survived the battle with the Romans only to die days or weeks later from infection. Common in the soil at Kalkriese is the bacterium known as tetanus, which would be a painful death to anyone who was infected with it. Gangrene is another commonly found bacterium that would mean certain death if not caught in time. Septicemia, commonly known as blood poisoning, was the third most common form of death on the ancient battlefield; this occurred if a blood vessel had been injured and then became infected; it meant certain death, but of the three infections septicemia was the least common.

The End of the Battle

At the end of the third day of the battle, lay dead about 16,500 Roman soldiers and an estimated 500 Germanic warriors. The streams that flowed into the bog ran red with blood from the dead who lay as many as three deep on the short narrows of the path. In the bog were floating several bodies of Roman legionaries who had dropped their armour and everything else they could drop as they attempted to swim away from the battle. The attack happened so fast and jammed the Roman column so much that not one of the nearly 25,000 Roman javelins was thrown. Bronze cooking ware, iron tools, bronze and silver coins as well as personal items of the Roman soldiers were thrown about everywhere in the madness of the battle. Away from the main battle site at the front of the column, the battle dead were more scattered in the middle and end of the column as a retreat was tried but failed when the Germanic warriors cut off and killed the retreating Romans away from the defile.