After defeating the Latins in 496 BC at the Battle of Lake Regillus, the Romans did not enjoy peace for long. Two years later, the Volscians, a tribe of Italy to the southeast, entered Roman territory. The consuls attempted to muster the army, but all of the infantry refused to fight. They instead poured out into the streets and began to riot.
Ancient Rome consisted of three classes: Patrician (aristocrats), Equestrian (the wealthy) and Plebeian (the commoners). The Plebeians were upset because, during Rome's almost continual fighting, the burden of warfare fell almost entirely upon their class. In the 5th century BC, most plebeians worked small farms outside of Rome. When they went off to fight a battle, they were no longer able to tend to their farms, and so hurt financially. Moreover, most of the fighting would be done upon their land, and their was a chance that their crops and homes would be destroyed in the fighting. Many infantrymen, who could not pay their taxes, became slaves to their creditors.
The Patricians saw that they now had two enemies: the Volscians outside and the Plebeians within. They had to make concessions, or Rome would be destroyed. The Plebeians formed the Roman infantry, which was the bulwark of the Roman army. Seeing no alternative, the Senate passed a law that stated no Roman citizen could be enslaved and that no soldier on active military duty could have his property confiscated. The consuls promised that more concessions would be forthcoming, but only after the Volscians had been defeated.
Upon hearing this, the Plebeians gladly filled the ranks of the Roman army. The Volscians and several other enemies were easily overcome. After the victories, however, no new laws were passed and the previous concessions not enforced. Soon enough, in 494 BC, the Plebeians once again refused to fight. To make a more dramatic statement, this time they departed to the Sacred Mount, or perhaps some other hill, outside of the city of Rome. Fearing that once again enemies would invade Roman territory and they would lack an army, concessions were made. The magistracy of the Tribune was created, to protect the rights of the Plebeians.
Through these two actions and continued pressure upon the Patricians, the Plebeians won more and more rights for themselves. The growing problem that they found, however, was that they were at the mercy of the consuls and other magistrates to enforce those laws. The Plebeians needed the legal code spelled out for them, so that they would know their rights and when they had been violated.
Out of this need rose the establishment of the decemviri ('ten men') in 451 BC. Their task was to right out the Roman legal code in clear wording so that all would know their rights. Ten Patricians were elected as decemvirs for one year to accomplish this task. At the end of the year, they had written down many laws, written out in copper on long tables. Their task had not been finished, however. Therefore, ten new men were elected the next year, but this time five of them were Patricians. During this year, they created two more. Rome now had her famous Twelve Tables, which spelled out the laws for each social class of Rome. These formed the basis of the Roman legal system, and hence the legal codes of all western nations, even in the present day.
With the purpose of the decemvirs completed, it was assumed that the old offices of the Republic would be resumed. In fact, all looked forward to a return to the old ways, since the decemvirs, who enjoyed absolute power, had begun to act more and more as ten tyrants. Yet time went on, and no elections were announced.
Many of the Patricians attempted to restore the Republic in the Senate, but their debates accomplished little. Hearing of this, the Plebeians took matters into their own hands. For the second time, they left Rome and took up residence on the Sacred Mount. They demanded the reestablishment of the office of Tribune to protect their rights. With no alternative, the decemvirs relented. Once again in power, the Tribunes wrested control away from the decemvirs, and the Republic was once again restored in 449 BC.
From this point on, the different social classes reached an uneasy truce. The only significant new right the Plebeians was to be able to marry into the Patrician class. Still, the embers of the conflict always smoldered beneath the surface of Republican Rome.
Livy. Ab Urbe Condita.