The Senate was a strictly aristocratical body, practically a co-optative body, for every five years the Censor, himself a Senator, revised the list of the Senate. It was in his power to remove members, who had in various ways disgraced themselves, or who had fallen below the property qualification demanded of a Senator; he could summon new members, and though, after Sulla had passed a decree to that effect, he was bound to summon all men who had held the elective office of Quæstor, so long as the Senate was united, it could control the elections, and take care that no undesirable politician should in this way effect his admission to the order. This quality of an Aristocratical Order still hung about the Senate in the early days of the Empire; it was felt even then to be a public misfortune that a Senatorial family should be unequal to maintaining its position, and such families were occasionally subsidised by the Emperors. The Senate was chiefly composed of men who belonged to an aristocracy by birth, and it admitted new men very unwillingly; a Marius with the power of the Army behind him could force his way into the Senate; a useful advocate like Cicero, or general like Pompeius, could be summoned to its ranks, but such men were unwelcome; they were accepted as a disagreeable necessity; all three learned at different times by bitter experience, that they were, at the best, tolerated. An indication of the aristocratic nature of the Senate is afforded by the fact that Senators were forbidden to engage in trade, a prohibition which however they contrived to evade.