For centuries, the Romans created and maintained the largest Empire of the Antiquity.
This way they spread their Greek-influenced culture, and influenced the subsequent European cultures.
About 40 % of the people in the European Union speak a language of Latin origin (French, Italian, Spanish, Portuguese, Romanian and others).
But the base of the Roman Empire was the force of their army and when the Roman army weakened, the Empire fell. In ancient Rome, all the handy men (except the poor ones) were enrolled in the army till they were 30 and were kept as reserves for another 14 years. Initially, the soldiers paid for their equipment, but after a while, they turned professional. In critical moments, mercenaries were employed.
The pedites (infantry) were assigned in principes (first line soldiers), triarii (reserves) and hastati (spear throwers). There were also auxiliary troops, formed by allies or incorporated troops from the conquered territories. The Romans also had chivalry, made especially from patrician sons, and divided in decuriae (lines of ten); three decuriae formed a turma (squadron). Chivalry had little use in the Roman army and was more a means of ascension.
A normal infantry troop bore a cassis (helmet) made of bronze or leather; a metal, leather or skin lorica (armor), a large and heavy scutum (shield), glaucius (sword) which was short, double bladed and a pilum (lance), 1.8 m long. A centurion (commander of 100 troops) bore on his helmet a tuft and also a vitis (vine branch), both pointing to his rank. The Roman standard bore the eagle (which was the symbol of a legion) and the letters SPQR (Senatus Populusque Romanum), its motto, as the symbol of the balance between democracy and people. The standard was born by the aquilifer, the bravest soldier.
The soldiers number in a legion varied between 4.200 and 6.000 infantry troops, divided in centurias (100 troops), manipulos (two centurias) and cohorts (three centurias). Ten cohorts formed a legion.
The attack consisted in infantry advance till it was situated a few steps away from the enemy troops, to throw the spears and proceed on side to side fight with the swords. Once the enemy troops moved back or gave up positions, the chivalry (some 300 riders for each legion) annihilated or made prisoners the defeated.
Three Roman military tactics are famous.
One is the testudo (turtle) (image), which received its fame due to the stories of Asterix and Oberlix, in which the soldiers formed a compact rectangular form protected by shields from flank, front, rear and above against arrows and stones.
Triplex Acies was used by Julius Cesar. Soldiers were disposed in three lines: four cohorts in the first, three in the second and other three in the third.
Half moon formation was inspired by the Hannibal's troops and consisted in surrounding the enemy troops with the infantry, while the chivalry was staying on the rear guard.