While Gracchus thus leaned on the support of the multitude, which partly expected, partly received from him a material improvement of its position, he laboured with equal energy at the ruin of the aristocracy.  Perceiving clearly how insecure was the rule of the head of the state built merely on the proletariate, he applied himself above all to split the aristocracy and to draw a part of it over to his interests.  The elements of such a rupture were already in existence.  The aristocracy of the rich, which had risen as one man against Tiberius Gracchus, consisted in fact of two essentially dissimilar bodies, which may be in some measure compared to the peerage and the city aristocracy of England.  The one embraced the practically closed circle of the governing senatorial families who kept aloof from direct speculation and invested their immense capital partly in landed property, partly as sleeping partners in the great associations.  The core of the second class was composed of the speculators, who, as managers of these companies, or on their own account, conducted the large mercantile and pecuniary transactions throughout the range of the Roman hegemony.  We have already shown(16) how the latter class, especially in the course of the sixth century, gradually took its place by the side of the senatorial aristocracy, and how the legal exclusion of the senators from mercantile pursuits by the Claudian enactment, suggested by Gaius Flaminius the precursor of the Gracchi, drew an outward line of demarcation between the senators and the mercantile and moneyed men.  In the present epoch the mercantile aristocracy began, under the name of the -equites-, to exercise a decisive influence in political affairs.  This appellation, which originally belonged only to the burgess-cavalry on service, came gradually to be transferred, at any rate in ordinary use, to all those who, as possessors of an estate of at least 400,000 sesterces, were liable to cavalry service in general, and thus comprehended the whole of the upper society, senatorial and non-senatorial, in Rome.  But not long before the time of Gaius Gracchus the law had declared a seat in the senate incompatible with service in the cavalry,(17) and the senators were thus eliminated from those qualified to be equites; and accordingly the equestrian order, taken as a whole, might be regarded as representing the aristocracy of speculators in contradistinction to the senate.  Nevertheless those members of senatorial families who had not entered the senate, especially the younger members, did not cease to serve as equites and consequently to bear the name; and, in fact, the burgess-cavalry properly so called—­that is, the eighteen equestrian centuries—­in consequence of being made up by the censors continued to be chiefly filled up from the young senatorial aristocracy.(18)