At one extreme is the Emperor and other powerful families of Rome. These individuals were incredibly wealthy. For example, Emperor Caligula's favorite horse, Incitaus, lived better than most Romans. Incitaus lived in an ivory manger with a golden cup from which to drink his expensive wine.
On the other side, most Romans lived in apartments that were notoriously filthy and prone to fire, and a solid 40% of the people living in Rome were slaves.
When writing a novel, it is so easy to focus in on the MC and not see the variety of people living around him or her. But like the slaves that make up almost half of the Roman population, we can't forget about the people who surround the MC. While the general populous may fade into the background of the novel, they still influence the experiences and the voice of the MC.