The Complete Aristotle (eng.)

imposition of public services, and sometimes they
bring accusations against the rich that they may have their wealth
to confiscate.
    Of old, the demagogue was also a general, and then democracies
changed into tyrannies. Most of the ancient tyrants were originally
demagogues. They are not so now, but they were then; and the reason
is that they were generals and not orators, for oratory had not yet
come into fashion. Whereas in our day, when the art of rhetoric has
made such progress, the orators lead the people, but their
ignorance of military matters prevents them from usurping power; at
any rate instances to the contrary are few and slight. Tyrannies
were more common formerly than now, for this reason also, that
great power was placed in the hands of individuals; thus a tyranny
arose at Miletus out of the office of the Prytanis, who had supreme
authority in many important matters. Moreover, in those days, when
cities were not large, the people dwelt in the fields, busy at
their work; and their chiefs, if they possessed any military
talent, seized the opportunity, and winning the confidence of the
masses by professing their hatred of the wealthy, they succeeded in
obtaining the tyranny. Thus at Athens Peisistratus led a faction
against the men of the plain, and Theagenes at Megara slaughtered
the cattle of the wealthy, which he found by the river side, where
they had put them to graze in land not their own. Dionysius, again,
was thought worthy of the tyranny because he denounced Daphnaeus
and the rich; his enmity to the notables won for him the confidence
of the people. Changes also take place from the ancient to the
latest form of democracy; for where there is a popular election of
the magistrates and no property qualification, the aspirants for
office get hold of the people, and contrive at last even to set
them above the laws. A more or less complete cure for this state of
things is for the separate tribes, and not the whole people, to
elect the magistrates.
    These are the principal causes of revolutions in
democracies.
VI
    There are two patent causes of revolutions in oligarchies: (1)
First, when the oligarchs oppress the people, for then anybody is
good enough to be their champion, especially if he be himself a
member of the oligarchy, as Lygdamis at Naxos, who afterwards came
to be tyrant. But revolutions which commence outside the governing
class may be further subdivided. Sometimes, when the government is
very exclusive, the revolution is brought about by persons of the
wealthy class who are excluded, as happened at Massalia and Istros
and Heraclea, and other cities. Those who had no share in the
government created a disturbance, until first the elder brothers,
and then the younger, were admitted; for in some places father and
son, in others elder and younger brothers, do not hold office
together. At Massalia the oligarchy became more like a
constitutional government, but at Istros ended in a democracy, and
at Heraclea was enlarged to 600. At Cnidos, again, the oligarchy
underwent a considerable change. For the notables fell out among
themselves, because only a few shared in the government; there
existed among them the rule already mentioned, that father and son
not hold office together, and, if there were several brothers, only
the eldest was admitted. The people took advantage of the quarrel,
and choosing one of the notables to be their leader, attacked and
conquered the oligarchs, who were divided, and division is always a
source of weakness. The city of Erythrae, too, in old times was
ruled, and ruled well, by the Basilidae, but the people took
offense at the narrowness of the oligarchy and changed the
constitution.
    (2) Of internal causes of revolutions in oligarchies one is the
personal rivalry of the oligarchs, which leads them to play the
demagogue. Now, the oligarchical demagogue is of two sorts: either
(a) he practices upon the oligarchs themselves (for, although the
oligarchy are quite a small number, there may be a demagogue among
them, as at Athens Charicles’ party won power by courting the
Thirty, that of Phrynichus by courting the Four Hundred); or (b)
the oligarchs may play the demagogue with the people. This was the
case at Larissa, where the guardians of the citizens endeavored to
gain over the people because they were elected by them; and such is
the fate of all oligarchies in which the magistrates are elected,
as at Abydos, not by the class to which they belong, but by the
heavy-armed or