In addition to the clients there were actual slaves, who were the property of their masters, and could be bought or sold at pleasure. Sometimes a slave was freed, and then he was called a LIBERTUS (freedman) and became the client of his former master.
As Rome grew into commercial prominence, still another class of people flocked into the city from foreign places, who might be called resident foreigners, corresponding in general to the _Metics_ at Athens. Such were many merchants and workmen of all trades. These all were supposed to be under the protection of some patrician who acted as their patron.
These three classes, clients, slaves, and resident foreigners, were all of a different race from the Romans. This should be constantly borne in mind.
We have learned that Rome, as she grew in power, conquered many of the Latin towns, and added their territory to hers. The inhabitants of these towns were of the same race as the Romans, but were not allowed any of their civil rights. Most of them were farmers and peasants. Many of them were wealthy. This class of inhabitants on the _ager Romanus_, or in Rome itself, were called Plebeians (_Plebs_, multitude). Their very name shows that they must have been numerous. They belonged to no gens or curia, but were free, and allowed to engage in trade and to own property. In later times (from about 350) all who were not Patricians or slaves were called Plebeians.
Until the time of Servius Tullius (about 550) the army was composed entirely of patricians. It was called a Legio (a word meaning _levy_), and numbered three thousand infantry called _milites_, from _mille_, a thousand, one thousand being levied from each tribe. The cavalry numbered three hundred at first, one hundred from each tribe, and was divided into three companies called Centuries.
During the reign of Servius the demands of the plebeians, who had now become numerous, for more rights, was met by the so called SERVIAN reform of the constitution. Heretofore only the patricians had been required to serve in the army. Now all males were liable to service. To accomplish this, every one who was a land-owner, provided he owned two acres, was enrolled and ranked according to his property. There were five "Classes" of them. The several classes were divided into 193 subdivisions called "Centuries," each century representing the same amount of property. In the first class there were forty centuries in active service, composed of men under forty-six, forty centuries of reserve, and eighteen centuries of cavalry.