Roman army is attributed to Romulus, who formed it on the tribal
principle, each of the three tribes contributing its contingent of horse
and foot. But it was to Servius Tullius that Rome owed, traditionally,
the complete classification of her citizen-soldiers. For the details of
the Roman military system, see ROMAN ARMY. During the earlier period of
Roman history the army was drawn entirely from the first classes of the
population, who served without pay and provided their own arms and
armour. The wealthiest men (_equites_) furnished the cavalry, the
remainder the infantry, while the poorer classes either fought as light
troops or escaped altogether the privilege and burden of military
service. Each "legion" of 3000 heavy foot was at first formed in a solid
phalanx. The introduction of the elastic and handy three-line formation
with intervals (similar in many respects to Alexander's) was brought
about by the Gallic wars, and is attributed to M. Furius Camillus, who
also, during the siege of Veii, introduced the practice of paying the
soldiers, and thus removed the chief obstacle to the employment of the
poorer classes. The new order of battle was fully developed in the
Pyrrhic Wars, and the typical army of the Republic may be taken as
dating from the latter part of the 3rd century B.C. The legionary was
still possessed of a property qualification, but it had become
relatively small. An annual levy was made at Rome to provide for the
campaign of the year. Discipline was severe, and the rewards appealed as
much to the soldier's honour as to his desire of gain. A legion now
consisted of three lines (_Hastati, Principes, Triarii_), each line
composed of men of similar age and experience, and was further
subdivided into thirty "maniples," each of two "centuries." The normal
establishment of 300 cavalry, 3000 heavy and 1200 light infantry was
still maintained, though in practice these figures were often exceeded.
In place of the old light-armed and somewhat inferior _rorarii_, the new
_velites_ performed light infantry duties (211 B.C.), at the same time
retaining their place in the maniples, of which they formed the last
ranks (compare the Macedonian phalanx as reorganized in 323, S 7 above).
The 300 cavalry of the legion were trained for shock action. But the
strength of the Roman army lay in the heavy legionary infantry of
citizens. The thirty maniples of each legion stood in three lines of
battle, but the most notable point of their formation was that each
maniple stood by itself on its own small manoeuvre-area, free to take
ground to front or flank. To the Roman legion was added a legion of
allies, somewhat differently organized and possessing more cavalry, and
the whole force was called a "double legion" or briefly a "legion." A
consul's army consisted nominally of two double legions, but in the
Punic wars military exigencies rather than custom dictated the numbers
of the army, and the two consuls at Cannae (216 B.C.) commanded two
double consular armies, or eight double legions.