The Roman social structure:1. Tacitus described the leading social groups of the early empire as follows: senators (patres, lit. ‘fathers’); leading members of the equestrian class; the respectable section of the people, those attached to the great houses; the unkempt lower class (plebs sordid) who, he tells us, were addicted to the circus and theatrical displays; and finally the slaves.
In the early third century when the Senate numbered roughly 1,000 approximately half of all senators still came from Italian families.
2. By the late empire, which starts with the reign of Constantine I in the early part of the fourth century, the first two groups mentioned by Tacitus (the senators and the equites) had merged into a unified and expanded aristocracy, and at least half of all families were of African or eastern origin.
This ‘late Roman’ aristocracy was enormously wealthy but in many ways less powerful than the purely military elites who came almost entirely from non-aristocratic backgrounds.
3. The ‘middle’ class now consisted of the considerable mass of persons connected with imperial service in the bureaucracy and army but also the more prosperous merchants and farmers of whom there were many in the eastern provinces.
Tacitus described this ‘respectable’ middle class as clients of the great senatorial houses. Now it was chiefly Government service and dependence on the State that sustained many of these families. Below them were the vast mass of the lower classes known collectively as humiliores (lit. ‘lower’).
4. They comprised a rural labour force of which many were permanently employed on the large estates; workers in industrial and mining establishments; migrant workers who supplied much of the labour for the grain and olive harvests and for the building industry; self -employed artisans who, it was said, were better fed than wage labourers; a large mas of casual labourers, especially in the big cities; and of course the many thousands of slaves that were still found all over the western empire in particular.