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