Historical background Despite the importance given to the theme of peace in Augustus' imperial propaganda, his principate was marked by a greater war effort than during the reign of most of his successors. Only the emperors
Trajan and
Marcus Aurelius had to fight simultaneously on several fronts, as Augustus did. His reign saw the extension of almost all the Empire's frontiers, from the
North Sea to the
Black Sea, from the
Cantabrian mountains to the
Ethiopian desert, with the strategic aim of completing the establishment of Roman domination over the whole of the
Mediterranean basin and Europe, shifting the frontiers to the north towards the
Danube and to the east towards the
Elbe (instead of the Rhine). Augustus' campaigns were conducted to consolidate the disorganized acquisitions of the
Republican era, which involved the annexation of numerous territories. While the situation in the East could be maintained as
Pompey and
Mark Antony had left it, in the West, a territorial reorganization between the Rhine and the Black Sea appeared necessary to guarantee internal stability and, at the same time, more defensible frontiers.
Preparing for conflict With
Agrippa's help, Augustus prioritized completing, once and for all, the subjugation of the “internal zones” of the Empire that had not yet been fully conquered. First and foremost, he proceeded with the definitive subjugation of the north-western Iberian peninsula, which had been a problem for decades. These territories were only finally brought under Roman domination after a series of difficult and bloody expeditions, the
Cantabrian Wars, which lasted 10 years (from 29 to 19 BC) and involved numerous
legions (up to 7) and an equally large number of
auxiliary troops, to the extent that Octavian's presence in the theater of operations was necessary (between 26 and 25 BC). This campaign was followed by another in the
Alps, aimed at securing the border and roads between
Italy and
Gaul: • 26–25 BC These two years of campaigning were devoted to subduing the populations settled around the
Great St Bernard Pass, under the joint action of generals
Aulus Terentius Varro Murena, who operated from the south against the
Salassi people, and
Marcus Vinicius, in the north, as
legate of chevelue Gaul, who subdued the population of
Vallis Poenina (today's
Valais). • 23 BC The city of
Tridentium (
Trento) is fortified, helping to make it a military stronghold for the future campaigns of General
Drusus, a few years later (see below in 15 BC).
The opposing forces During two decades of warfare between
northern Italy and
Gaul,
Augustus was able to deploy an army made up of numerous
legions and
auxiliary units. At one time or another, the following legions were involved: • on the
Gaul front:
legion I Germanica,
legion V Alaudae,
legion XIV Gemina Martia Victrix,
legion XVI Gallica,
legion XVII and
legion XVIII; • on the
Italian/
Illyrian front:
legion IX Hispana,
legion XIII Gemina,
legion XIX,
legion XX Valeria Victrix and
legion XXI Rapax.
Military campaigns • 16 B.C , including
Rhaetia and
Vindelicia.
Tiberius, just appointed
praetor, accompanies Augustus to
Gaul, where he spends the next three years, until 13 BC, assisting him in the organization and administration of the Gallic provinces. The princeps also took his son on a punitive campaign across the
Rhine against the tribe of
Sicambres and their allies
Tencteres and
Usipetes, who in the winter of 17–16 BC defeated
proconsul Marcus Lollius Paulinus, resulting in the partial destruction of
legio V Alaudae and the loss of its insignia.
Publius Silius Nerva, governor of
Illyria, completes the conquest of the eastern Alps with the subjugation of the valleys from
Como to
Lake Garda (including the
Camunni of
Val Camonica), as well as the
Venostes of
Val Venosta (in
Alto Adige). Taking advantage of the absence of the
Legate of Augustus, the
Pannonians, and
Norics invaded
Istria. The Roman general's reaction was swift, with the occupation of southern
Noricum and the institution of a kind of vassal status for the kingdom of northern Noricum (
Taurisci people). • 15 B.C
Tiberius and his brother
Drusus carry out operations against the
Rhaetian, settled between
Noricum and
Gaul, and the
Vindelici. Drusus had previously cut the Rhaetians off from Italian territory, where they had carried out numerous raids, but Augustus decided to send Tiberius to stabilize the situation once and for all. The two commanders, in an attempt to encircle the enemy by attacking him on two fronts without giving him the chance to flee, planned a “pincer” attack, which their lieutenants put into effect: Tiberius attacked from
Helvetia, while his younger brother divided his army, which had left
Aquileia for
Trento, into two parts. The
first column crossed the valleys of the
Adige and
Isarco rivers (at the confluence of which they built the
Pons Drusi (Drusus Bridge) near present-day
Bolzano), to reach the
Inn; the second followed what was to become the
Via Claudia Augusta under Emperor
Claudius (built by his father Drusus), crossing the
Val Venosta and the
Reschen pass, also to reach the Inn. Tiberius, advancing from the west, defeated the
Vindelici in the vicinity of
Basel and
Lake Constance; it was here that the armies came together and prepared to invade
Vindelicia. Drusus had meanwhile subdued the Breunes and
Genauni peoples. These successes enabled Augustus to subdue all the populations of the Alpine arc as far as the Danube and earned him the right to be acclaimed
Imperator once again, while Drusus, Augustus's favorite son, would later win a
triumph for this and other victories. In the mountains of the southern Alps, near present-day
La Turbie, the emperor erected the
Alpine Trophy to commemorate these conquests. • 14 B.C The
Ligurian Comati of the
Maritime Alps are partly subjected to the praefecti civitatum, the other part being annexed to the kingdom of
Cottius, son of a local potentate officially appointed prefect by Augustus. At the end of the operations, it seems that two legions were left to guard the conquered territories of
Vindelicia, one at Dangstetten, and one at
Augusta Vindelicorum. == Consequences ==