The senatorial order (ordo senatorius) was one of the two leading groups in Roman society: it occupied the most important offices in the administrative machine - in politics, justice and the army, to be more precise. It was Augustus who defined the limits of the senatorial order more clearly vis-a-vis the order immediately next in rank, that of the equestrians. The senatorials were thus a small, closed social group, of some six hundred members. From the 2nd century A.D. onwards, a significant increase in the number of Roman provincial subjects accepted for the Senate is noticeable. This meant that it ceased to be a body politic of the city of Rome, and gradually turned into an exclusive representative organ of the empire as a whole. Members of the senatorial order were distinguished sartorially by a chiton with a broad purple stripe.

Senatorials were known for their wealth, their luxury lifestyle, and also, very often, their open-handedness. Certain well-endowed senatorial families would make donations for public works in the eastern provinces. Herodes Atticus' father famously made 4,000,000 denarii available for irrigation works at Troy, and also aided Athens with gifts of money and even doles of sacrificial meat and wine. Herodes, in his turn, made a great number of donations in Hellas. More precisely, he rebuilt the Panathenaic stadium and the Odeum of Regilla, at Athens; a stadium at Delphi; and an aqueduct at Olympia.