which is exact. One purpose of the Roman census was to determine the ordo to which an individual belonged. The two highest ordines in Rome were the senatorial and equestrian. Outside Rome, the decurions, also known as curiales (Greek bouleutai), were the top governing ordo of an individual city. "Senator" was not itself an elected office in ancient Rome; an individual gained admission to the Senate after he had been elected to and served at least one term as an executive magistrate. A senator also had to meet a minimum property requirement of 1 million sestertii, as determined by the census. Nero made large gifts of money to a number of senators from old families who had become too impoverished to qualify. Not all men who qualified for the ordo senatorius chose to take a Senate seat, which required legal domicile at Rome. Emperors often filled vacancies in the 600-member body by appointment. A senator's son belonged to the ordo senatorius, but he had to qualify on his own merits for admission to the Senate itself. A senator could be removed for violating moral standards: he was prohibited, for instance, from marrying a freedwoman or fighting in the arena. In the time of Nero, senators were still primarily from Rome and other parts of Italy, with some from the Iberian peninsula and southern France; men from the Greek-speaking provinces of the East began to be added under Vespasian. The first senator from the most eastern province, Cappadocia, was admitted under Marcus Aurelius. By the time of the Severan dynasty (193–235), Italians made up less than half the Senate. During the 3rd century, domicile at Rome became impractical, and inscriptions attest to senators who were active in politics and munificence in their homeland (patria). Senators had an aura of prestige and were the traditional governing class who rose through the cursus honorum, the political career track, but equestrians of the Empire often possessed greater wealth and political power. Membership in the equestrian order was based on property; in Rome's early days, equites or knights had been distinguished by their ability to serve as mounted warriors (the "public horse"), but cavalry service was a separate function in the Empire. A census valuation of 400,000 sesterces and three generations of free birth qualified a man as an equestrian. The census of 28 BC uncovered large numbers of men who qualified, and in 14