Publius Quinctilius Varus in the context of "AD 1"

The Roman campaigns in Germania (12 BC – AD 16) were a series of conflicts between the Germanic tribes and the Roman Empire. Tensions between the Germanic tribes and the Romans began as early as 17/16 BC with the Clades Lolliana, where the 5th Legion under Marcus Lollius was defeated by the tribes Sicambri, Usipetes, and Tencteri. Roman Emperor Augustus responded by rapidly developing military infrastructure across Gaul. His general, Nero Claudius Drusus, began building forts along the Rhine in 13 BC and launched a retaliatory campaign across the Rhine in 12 BC.

Drusus led three more campaigns against the Germanic tribes in the years 11–9 BC. For the campaign of 10 BC, he was celebrated for being the Roman who traveled farthest east in northern Europe. Succeeding generals would continue attacking across the Rhine until AD 16, notably Publius Quinctilius Varus in AD 9. During the return trip from his campaign, Varus' army was ambushed and almost destroyed by a Germanic force led by Arminius at the Battle of the Teutoburg Forest; Arminius was the leader of the Cherusci, had previously fought in the Roman army, and was considered by Rome to be an ally. Roman expansion into Germania Magna stopped as a result, and all campaigns immediately after were in retaliation of the Clades Variana ("Varian Disaster"), the name used by Roman historians to describe the Battle of the Teutoburg Forest, and to prove that Roman military might could still overcome German lands. The last general to lead Roman forces in the region during this time was Germanicus, the adoptive son of Emperor Tiberius, who in AD 16 had launched the final major military expedition by Rome into Germania.

The clades Lolliana or Lollian disaster was a battle in 16 BC, when the consul Marcus Lollius was defeated by the Sicambri, Usipetes and Tencteri, Germanic tribes who had crossed the Rhine. This defeat is coupled by the historian Suetonius with the disaster of Publius Quinctilius Varus in the Battle of the Teutoburg Forest.

After capturing and crucifying Romans in their own lands, the three Germanic tribes crossed the Rhine and plundered Roman territory. Roman cavalry were ambushed and routed. While pursuing the cavalry, the Germani came across the Roman governor Lollius and defeated him as well. They captured the eagle of the fifth legion. When Lollius and Augustus began to assemble armies, the Germani retreated back to their own lands, made peace and gave hostages.

Arminius (/ɑːrˈmɪniəs/; 18/17 BC–AD 21; Hermann in German) was a chieftain of the Germanic Cherusci tribe who is best known for commanding an alliance of Germanic tribes at the Battle of the Teutoburg Forest in AD 9, in which three Roman legions under the command of general and governor Publius Quinctilius Varus were destroyed. His victory at Teutoburg Forest precipitated the Roman Empire's permanent strategic withdrawal and the deprovincialization of Germania Magna, and modern historians regard it as one of Imperial Rome's greatest defeats. As it prevented the Romanization of Germanic peoples east of the Rhine, it has also been considered one of the most decisive battles in history and a turning point in human history.

Born a prince of the Cherusci tribe, Arminius was part of the Roman-friendly faction of the tribe. He learned Latin and served in the Roman military, which gained him Roman citizenship, and the rank of eques. After serving with distinction in the Great Illyrian Revolt, he was sent to Germania to aid the local governor Publius Quinctilius Varus in completing the Roman conquest of the Germanic tribes. While in this capacity, Arminius secretly plotted a Germanic revolt against Roman rule, which culminated in the ambush and destruction of three Roman legions in the Teutoburg Forest.

The Battle of the Teutoburg Forest, also called the Varus Disaster or Varian Disaster (Latin: Clades Variana) by Roman historians, was a major battle fought between an alliance of Germanic peoples and the Roman Empire between 8 and 11 September 9 AD, possibly near modern Kalkriese. Fighting began with an ambush by the Germanic alliance on three Roman legions being led by Publius Quinctilius Varus and their auxiliaries; the alliance was led by Arminius, a Germanic chieftain and officer of Varus's auxilia. Arminius had received Roman citizenship and a Roman military education, thus allowing him to deceive the Romans methodically and anticipate their tactical responses.

Teutoburg Forest is considered one of the most important defeats in Roman history, bringing the triumphant period of expansion under Augustus to an abrupt end. It dissuaded the Romans from pursuing the conquest of Germania, and so can be considered one of the most important events in European history.

Kalkriese is a village now administratively part of the city of Bramsche in the district of Osnabrück, Lower Saxony, Germany. It is on the northern slope of the Wiehen Hills, a ridge-like range of hills, north of Osnabrück. The Kalkrieser Berg or Schmittenhöhe, a hill with a height of 157 m (515 ft), is considered by archaeologists to be the likely site of the Battle of the Teutoburg Forest.

The Battle of the Teutoburg Forest (German: Schlacht im Teutoburger Wald, Hermannsschlacht or Varusschlacht), described as clades Variana (the "Varian disaster") by Roman historians, took place in what the Romans called the saltus Teutoburgiensis and has since been identified as Kalkriese in 9 AD, when an alliance of Germanic tribes ambushed and decisively destroyed three Roman legions and their auxiliaries, led by Publius Quinctilius Varus. The anti-Roman alliance was led by Arminius, an officer of Varus' auxiliary forces who had acquired Roman citizenship and received a Roman military education.