It is a popular myth that the Roman Republic was ruled by Patricians and that the common people were Plebeian. In the television series Rome, when Caesar appoints Lucius Vorenus to the Senate, Cicero protests because he is Plebeian. This is highly unlikely to have occurred as Cicero was himself of Plebeian birth1. By the late Republic the Senate was primarily composed of Plebeians, although some of the old Patrician families were still represented.
In short the population was broadly divided into three classes: those who were born free, those who had achieved freedom from slavery and lastly the slaves. The position you held in Roman society had an influence on the career that was open to you and on your status in public life so which class you belonged to was very important. There was extensive movement up and down between the classes so citizens who had very humble origins could achieve considerable status in Roman society.
In addition there were two other groups in Roman society, the largest consisted of peoples from lands conquered by Rome who were granted the status known as Latinitas or Latin rights2. This was a partial citizenship that granted the important right of protection by Roman law. Those who were very wealthy could buy citizenship, but this was unusual as the price was very high.
As an example of the class system in action, only men of the Senatorial or Noble class could command a legion or hold a rank above that of Centurion. Non-citizens from those areas ruled by Rome could normally only join the Auxiliary units not the Legions. Those who completed a full term of service in an Auxiliary unit were normally granted citizenship as reward for service.
To be a Patrician or Noble in Rome was to be a member of a family that had been considered noble before Rome became a republic. Originally the Patrician class had held all political power in republican Rome but this had been gradually whittled away. By the late republic all that being Patrician granted was a certain amount of status and the right to hold certain religious posts. Since entry to the Senate required ownership of property worth at least a million sesterces, some Patrician families were no longer represented in the Senate, others had died out and others had survived only by adoption3. Status was important and men belonging to the Senatorial class wore a tunic with broad vertical stripes (purple in colour) from shoulder to hem, known as the tunica laticlavia.
Also included in this class were the Equites or Equestrian class whose qualification for membership was to have property worth at least 400,000 sesterces. The Equestrian class could indulge in any form of trade or business whereas the Patrician and Senatorial classes were limited by custom and law to farming as their only legitimate form of trade4. Male members of this class wore a tunic with narrow vertical stripes from shoulder to hem, known as the tunica angusticlavia.
That the great mass of Roman citizens were Plebeian5 is true. However there was considerable variation in wealth and status within this class. Pompey the Great, whose family owned vast tracts of land in Umbria, was Plebeian. As the plebeians had won a share of political power in Rome some Plebeian families had become wealthy and as proud of their ancestry as any patrician aristocrat.
Political divides in Rome were not about class or a specific set of policies, rather they were about networks of alliances between individuals. In some ways the plebeian classes had more power than the patricians. Of the two counsels elected to rule Rome every year one had to be of Plebeian origin, but both could be and often were. The Tribunes of the Plebs, junior magistrates who had to be of Plebeian origin, could veto decisions taken by any of the other magistrates.
The men who originated from the populations of Roman territories were a class of freeborn foreigners known as Peregrini (freeborn non-Romans). These people were granted citizenship as Rome expanded the Empire and conquered or annexed their homelands.
The proletariat were the lowliest class of Roman society, freemen without property. As such they had no vote in any of the Roman assemblies although the mob, largely composed of proletarians, was a factor that Roman politicians had to consider.
Women were not regarded as citizens; they had no rights and could not vote. As far as legal status was concerned they had little more rights than slaves.
The lowest in the social order were the Liberti or ex-slaves. Manumission was the act of granting freedom to a slave. A slave was often granted freedom in a master's will, or if the master allowed, their freedom could be purchased. Also known as libertini, these freed slaves could become citizens, but their children were freeborn and their place of birth decided their status as either commoners or foreigners. Also depending upon the wealth of the parents they became either Plebeians or Proletarians from birth.