The Republican Roman Army
The Roman army in the third and second century BC was made out of four infantry types and one cavalry type:
Easily recognised by their distinctive fur caps, these guys were responsibly for weakening the enemy in the early stages of the battle. They evolved from levy troops with javelins to highly trained troops with sword, shield and throwing spears and javelins. the youngest and poorest of the Roman citizens formed these troops.
Gripping Beast Velites
The fur caps were used by their leaders to recognise the men during the battle to be able to reward or punish them afterwards for their behaviour.
The young adults formed the first line of the regular soldiers. They were the first to be armed with heavy throwing spears (pilum) and large shield. They wore a breastplate (pectorale) or even chain mail. There name still refers to an older organisation where the army was still equipped with the hasta (=thrusting spear).
The most important fighting force were the principes. they were usually light armoured troops with large shields. In the early period (in the wars against Pyrrhus) they were equipped with thrusting spears. later, during the Punic wars they used pila.
The last line of defence were the richest of the infantry. Often they wore the most expensive armour and large shields. For a very long time they kept using thrusting spears.
Gripping Beast republican Romans (left) & Navigator kneeling triarii (right)
The Triarii were the last line of defence for the Romans. The soldiers of the Triarii typically waited for the battle in a kneeling position.
When the Triarii were summoned to join in the fighting, the enemy easily could panic when this unsuspected new line stood up and advanced.
Eventually these units all disappeared when reforms by Gaius Marius made a legion of one type of unified soldier with pila and swords around 100 BC.
Marius is also known for another famous change in the weaponry, namely the weakening of the pila. Previous the pila was made very strong. So strong that the enemy often picked up thrown pila and threw them back. Marius made the connection between the long iron tip and the wooden shaft more vulnerable to breaking. This way, the pila broke on contact and it was not possible to throw it back. It is even said that when the pila got stuck in an enemies shield they rather threw away the shield and fought on without this protection than to keep on fighting with this spear stuck in the shield.
Cavalry always was Roman's weak point. But the Romans made extensive use of allied cavalry.
1st Corps & Gripping Beast republican Roman "haughty" command figures
Roman allies and enemies
During the republic, the Romans often fought their neighbours (like the Etruscans and Samnites), but they also joined them against aggressors from elsewhere (like the Celts or invading Epirotes from Greece).
Roman Tactical Formations
The Roman army changed a lot through it's history. After Rome loosened the ties with the Etruscans, the Roman army was made up like a Greek phalanx. There were 5 classes of soldiers (determined by how much money you owned). And a knights order, the equites. The army changes during the 4th century, fighting it's neighbours for the dominance of Italy and the invading Gauls.
The original classes kept on being used in one form or another. The early legions had the following differentiations:
The Veles, Rorarri and accensi were light troops.
By the second century BC things had changed again. The hastati were still up front. The other ranks of the legion were equipped with a long spear, the hasta, rather than the shorter pilum. The rorarii and accensii by now have been done away with, becoming velites. The velites were the more mobile troops who operated in the front of the army, stinging the enemy with their javelins, before retiring through the ranks of the hastati and principes
Subdivisions of all three ranks (hastati, principes, triarii) was one of ten maniples. A maniple is defined as consisting of 120 or 160 men. Each maniple was commanded by two centurions, the first centurion commanding the right, the second the left of the maniple.
The cavalry force of 300 men was divided into ten squadrons (turmae), each with three decuriones in command.
The maniples very manoeuvrable and were able to support each other. They could swap the front maniples, tired from the fight, with maniples behind them, still fresh.
Roman Baggage Camp