by Will Pearson
|Gallic leader, Brennus|
To the Roman Empire, nothing was more important than its army. It should be noted that the army’s importance was not just in the military defence of Rome, but it was also a political, social and economic force within the empire. For 700 years, the Roman philosophy was one of expansion, and so the world’s first superpower needed an outstanding army in order to fulfill its territorial ambitions. Furthermore, Rome’s legions quickly became the focus for political campaigns in both the republic and imperial eras, as military support almost guaranteed money and power. Financially, the spoils of war provided the main source of income for Rome, as well as a constant supply of slaves and newly established trade routes and partners. From a social perspective, serving time in the Roman army was a great honour, and entitled the lowest in society to gain citizenship as well as land and a pension. It is for these reasons, therefore, that the Roman military learned to adapt and evolve both tactically and in its composition.
As the empire grew, Rome would face widely differing enemies on varying terrains, from the guerilla tactics and cold forests of Germania to the nomadic cavalry and warm sands of Parthia. While the Roman army developed its doctrine for many reasons, arguably the most significant of these progressions came following Rome’s major defeats, for they were not common, and thus held great significance in Latin society.
Rome’s first major defeat came in 387 BC, following a land dispute with the Celtic Senones. During negotiations between Rome and the tribe concerning land rights, the Roman ambassadors, according to Livy, “Broke the law of nations” and “took up arms” against the Senones, resulting in the death of a Chieftain. The result was that the Gauls marched an army, under Brennus, 130km south from their position at Clusium in northern Italy towards Rome, engaging a hastily formed Roman army of about 24,000 men at the Battle of the Allia, 18km north of the Roman capital. The Romans were assembled in their standard phalanx formation, where special ‘hoplite’ troops are deployed in one long line and carry spears and pikes, with the weaker flanks protecting the heavier hoplites in the centre. When the Gauls, whose force numbered approximately half that of their opposition, attacked the Roman flanks, the young soldiers were routed instantly, those on the left fleeing to nearby Veii and the rest back to Rome. This breaking of the outer militia left the heavy units in the center exposed and easy to surround, leading to a massacre of Rome’s most skilled troops. When the rest of the army reached Rome, they barricaded themselves on the Capitoline Hill, and looked on as the pursuing Gallic army devastated the rest of the city, before succumbing to disease from the unburied dead. The ensuing peace talks became famous as Brennus threw his sword onto the weighing scales used for Roman reparations and declared “Woe to the vanquished”.
The Battle of the Allia and the subsequent sacking of Rome shocked the Roman military system, for the army needed to be more or less rebuilt from scratch. The annihilation of the aristocratic heavy infantry is probably the trigger for the formation of Triarii, Rome’s heaviest and most experienced troops, as a reserve force, even keeping the traditional hoplite long pike. Rome’s commanders had seen the weakness of the Greek phalanx tactics they had been using thus far, and so began a transition towards the manipular organisation that would serve them for the next 300 years. As well as replacing their tactical regime, the Romans drew inspiration from the Celts who had humiliated them by adopting full body shields of the kind that made a later Roman soldier so recognisable. The Romans then used this new equipment to develop their most famous tactical manoeuvre, the Testudo or ‘Tortoise’, where groups of soldiers surrounded themselves completely with shields for protection and advanced. Finally, the sacking of Rome following the Battle of the Allia showed the need for a greater system of defence through fixed fortifications, and the battle directly led to the construction of the Servian Wall around Rome, and this 10 metre high defensive structure was maintained until the early imperial days of Rome.
Overall, the Battle of the Allia, Rome’s first catastrophic defeat, had a huge influence on its military doctrine, as the Roman commanders began to mistrust their Greek phalanx tactics, and began adopting the equipment that would remain standard in their armies until the end of Roman civilization.