Aside from the Emperor and his near god-like status, one’s status derived essentially from two criteria.
Nobility—families of traditional, established position that usually dated to the founding years of early Rome. Hence the importance of tribe—one’s nomen (see Roman Naming Conventions) indicated that import familial-tribal relationship.
By the late Republic and imperial age, an individual’s census (monetary net worth) was determinative of either Senatorial status, the highest rank, or Equestrian status, the next in line. These two accounted for a mere one to five percent of the population—they were the elites. Next were those who held Roman citizenship which was highly prized. The remainder were the commoners, plebs, and those of the lowest—slaves.
This rigid hierarchy determined not only one’s status in the “pecking order” of society, but also the opportunities available for advancement to the next higher rung on the ladder.
An extremely visual expression of status was the seating positions in governmental buildings (the Senate Curia or provincial assemblies) and at theaters and other public buildings. The best seats are reserved for… guess who!