Social mobility in Hellenistic and Roman societies could come about in different ways, but was always a relatively rare occurrence. In practice, climbing the social ladder was a process that spanned generations. For the individual to rise socially, there were only three
Possible routes. Those who had acquired riches in commerce or industry could invest these in land and settle down as respectable landowners in the city; they themselves or their offspring would become citizens and after a while could even join the elite. Examples of such social mobility, however, are very scarce. Yet, such social climbing could not be ruled out, especially in the big cities of western Asia, but in all probability it must have been rare indeed. Another form of social mobility was provided by the armies of the period. In the Hellenistic kingdoms, professional soldiers and officers, usually of Greek or Macedonian origin, could in the royal service be promoted to high commands, be endowed with great riches, and end up as members of the landowning elite in Egypt or in one of the many new poleis in western Asia. In Rome too, the army offered to some degree a possible career for those with talent; common soldiers could sometimes and with some luck acquire enough booty to buy some land in Italy, or they could be promoted to the rank of subaltern officers. The rank of centurio was for them the highest achievable rank, and during the Roman Republic, this was infact almost unattainable, because most of the centuriones then were men of the equestrian order. In the late republic, the Roman army had become an army of mostly proletarians led by aristocratic officers; as long as the optimates dominated politics, there was not much room for social mobility. Under Caesar and Octavian, however, subalterns from the equestrian class were much more easily promoted to higher commands, a trend that would continue during the empire, while the possibilities for common soldiers to reach the centuriate would also be much enlarged. Finally, a last route for social mobility, paradoxically, passed through the stages of slavery and manumission. This route was especially of importance in Roman society, since the freedmen here became Roman citizens. Slavery was a massive phenomenon in the Roman world, and manumission of urban slaves occurred on a large scale. Many of those freed reinforced the ranks of the various middle groups in the city, but not a few also reached, albeit usually after two or three generations, the ranks of the elite. Numbers and percentages are, as usual, unknown, but it is likely that this third form of social mobility was in the late republic as well as in the early empire the most important of the three.