 The Romans did not see them as a threat, a mistake made too often in their history, and let them be. 

Ozment (2005, pg 18) goes on to describe how a Germanic tribe known as the Cimbri, crossed into Roman territory – modern day Austria – in 113 BC in search for food and land to live on. A Roman army confronted the tribe and a battle broke out in Noricum. Once the dust had settled, the Cimbri stood victorious, marking the first time in history that a Germanic tribe defeated a Roman army. Joined by the Teutones, the Cimbri drove the Roman army, which was sent to defeat them just four years later, back into Gaul. The continued to gain strength, and numbers and defeated two more Roman armies before finally being defeated. This not only marked one of the greatest military loses by a nomadic tribe to the Roman army, but also a period of unity between Germanic tribes. 

Though as Caesar noticed immediately, the inhabitants of Germania lusted for battle. Be it the Romans in their way in Noricum, or the Gauls taking the fertile land past the Rhine, the tribes were always ready to fight. This would be a great hindrance to complete unity in these early days, as they were not against also fighting each other. Tacitus noticed this trend as well, he wrote that the Germanic tribes would rather win something by battle and blood, than by wasting their sweat by doing manual labor. 

The Romans used this against the tribes, allowing them to destroy themselves with their own centrifugal forces. Still, some saw the possibility of assimilation. The belief was, that if tribal leaders could become civilized Romans, then they could change the barbaric lifestyle that the others live by. The children of major figures in Germania were offered invites to grow up in Rome, and were occasionally simply kidnapped (Ozment, 2005 pg. 20.) They would be raised as free men in the Roman Empire, where they would have land, receive an education and live as the Romans do. While some would chose to live there for the rest of their lives, others returned to their native lands as pro-Roman, Germanic tribesmen. 

This system occasionally backfired on the Romans. With tensions growing between the extremes of pro-Roman and near rebellion between the Romans and the Cherusci tribe, it was no surprise that the son of the chieftain: Arminius was sent to be raised in Rome. Arminius rose in rank in the Roman army, and took command of the German contingent in A.D 4. His service was greatly respected within the Roman world, however just 5 years later he would be leading his own warriors against the Romans who were hoping to expand into Germania. Arminius used guerrilla war tactics including ambushes in the thick Teutoberg forest as what (Ozment, 2005) claimed was an early use of the German blitzkrieg tactics. 

Arminius became a hero to all the Germans, and united great numbers of tribes into one force. 