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.

[9] Some of the descendants of the vassal kingdoms, like the Suebi (by suzerainty), that Augustus tried to create in Germania to expand the romanitas and the Empire were the ones that invaded Rome in the fourth and fifth centuries.

Octavian, now styled Augustus, aimed to solidify control of Gaul by dividing the region into three smaller provinces that emphasized the strategic importance of the Rhine valley.

After his return from Rome to Gaul, Arminius became a trusted advisor to Varus, the governor of the newly created Roman province of Germania,[29] even as he secretly constructed an alliance of Germanic peoples that had traditionally been enemies.

[30] Using the collective outrage over Varus' tyranny, insolence and cruelty to the conquered,[31] Arminius was able to unite the disorganized groups who had submitted to Rome, and maintain the alliance until the most opportune moment to strike.

[27] While Varus was on his way from his summer camp west of the River Weser to winter quarters near the Rhine, he heard reports of a local rebellion; these had been fabricated by Arminius.

[22] Edward Shepherd Creasy writes that "This was represented to Varus as an occasion which required his prompt attendance on the spot; but he was kept in studied ignorance of its being part of a concerted national rising; and he still looked on Arminius as his submissive vassal".

Varus acted to resolve the succession crisis at the death of Herod the Great in 4 BC, but his performance as governor is disputed by contemporary sources.

[34] Historian McNally assesses that Varus was not assigned to Germania for his military abilities, but for his political acumen; this was likely sought by the Emperor to deal with the factionalism among Germanic tribes.

From these events, McNally argues that Arminius surmised a key lesson: "the Romans could be defeated, but only in a situation where their tactical flexibility and discipline could not be brought to bear.

[46] Historical sources suggest that Varus waged little to no military action that summer, and instead focused on holding court and dealing with the Germanic tribes in a political and legal sense.

[47] At any rate, the summer was probably typical for the troops, whose time would have been spent drilling or engaging in civil engineering projects such as strengthening local roads and fortifications.

There, a sandy, open strip on which the Romans could march was constricted by the hill, so that there was a gap of only about 100 metres (330 ft) between the woods and the swampland at the edge of the Great Bog.

The road was further blocked by a trench and, towards the forest, an earthen wall had been built along the roadside, permitting the Germanic alliance to attack the Romans from cover.

The Romans made a desperate attempt to storm the wall, but failed, and the highest-ranking officer next to Varus, Legatus Numonius Vala, abandoned the troops by riding off with the cavalry.

[59][60] Upon hearing of the defeat, the Emperor Augustus, according to the Roman historian Suetonius in The Twelve Caesars, was so shaken that he stood butting his head against the walls of his palace, repeatedly shouting: Quintili Vare, legiones redde!

Arminius initially caught Germanicus' cavalry in a trap, inflicting heavy casualties, but the Roman infantry reinforced the rout and checked them.

A final battle was fought at the Angrivarian Wall west of modern Hanover, repeating the pattern of high Germanic fatalities, which forced them to flee beyond the Elbe.

Once his Germanic coalition had been broken and honour avenged, the huge cost and risk of keeping the Roman army operating beyond the Rhine was not worth any likely benefit to be gained.

Most of Germania Magna did not have the higher level of urbanism at this time as in comparison with some Celtic Gallic settlements, which were in many ways already integrated into the Roman trade network in the case of southern Gaul.

[90] Nonetheless, the Severan-era historian Cassius Dio is emphatic that Varus had been conducting the latter stages of full colonization of a greater German province,[91] which has been partially confirmed by recent archaeological discoveries such as the Varian-era Roman provincial settlement at Waldgirmes Forum.

[93] After Arminius was defeated and subsequently murdered in 21 AD by opponents within his own tribe, Rome tried to control Germania beyond the Limes indirectly, by appointing client kings.

[99] The theories about the location of the Battle of the Teutoburg Forest have emerged in large numbers especially since the beginning of the 16th century, when Tacitus' works Germania and Annales were rediscovered.

The main clue to its location was an allusion to the saltus Teutoburgiensis in section i.60–62 of Tacitus' Annals, an area "not far" from the land between the upper reaches of the Lippe and Ems rivers in central Westphalia.

This site, some 100 kilometres (62 mi) north west of Osning, was first suggested by the 19th-century historian Theodor Mommsen, renowned for his fundamental work on Roman history.

Once the dimensions of the project had become apparent, a foundation was created to organise future excavations and to build and operate a museum on the site, and to centralise publicity and documentation.

A long zig-zagging wall of peat turves and packed sand had apparently been constructed beforehand: concentrations of battle debris in front of it and a dearth behind it testify to the Romans' inability to breach the Germanic tribes' strong defence.

The museum houses a large number of artefacts found at the site, including fragments of studded sandals legionaries lost, spearheads, and a Roman officer's ceremonial face-mask, which was originally silver-plated.

The legacy of the Germanic victory was resurrected with the recovery of the histories of Tacitus in the 15th century, when the figure of Arminius, now known as "Hermann" (a mistranslation of the name "Armin" which has often been incorrectly attributed to Martin Luther), became a nationalistic symbol of Pan-Germanism.

[114] As a symbol of unified Romantic nationalism, the Hermannsdenkmal, a monument to Hermann surmounted by a statue, was erected in a forested area near Detmold, believed at that time to be the site of the battle.