When Vespasian sought to give new vitality to the decadent aristocracy of Rome by admitting the local gentry of the Italian towns to the senate, he was drawing upon a class which was destined to play an important part in the government and defence of the Empire. The municipal nobility, first of Italy and later of the provinces, not only managed the affairs of all the smaller communities, but also came to fill most positions of authority, both military and civil, in the imperial administration. To understand the Empire, therefore, we must know something of this aristocracy, and must study it in that local setting which our literary authorities despise. Here Pompeii affords valuable evidence, through the comparative abundance of the material presented, and through the tragic definiteness of its chronological lower limit. It is true that this evidence, for all its copiousness, is defective, since a large part of Pompeii remains unexcavated; and our lists of magistrates and of candidates for office are compiled from casual finds, not from official sources, so that negative evidence cannot safely be used. It is true also that Pompeii, owing to its unusually favourable economic conditions, is less representative of other Italian municipia than could be wished. Within these limits, however, a study of its ruling Ordo should throw some light upon the character of these bodies in and even beyond Italy.