d HELIAEA and its members HELIASTS.
Clisthenes also introduced the OSTRACISM, by which an Athenian citizen
might be banished without special accusation, trial, or defence for ten
years, which term was subsequently reduced to five. It must be
recollected that the force which a Greek government had at its disposal
was very small; and that it was comparatively easy for an ambitious
citizen, supported by a numerous body of partisans, to overthrow the
constitution and make himself despot. The Ostracism was the means
devised by Clisthenes for removing quietly from the state a powerful
party leader before he could carry into execution any violent schemes
for the subversion of the government. Every precaution was taken to
guard this institution from abuse. The senate and the ecclesia had
first to determine by a special vote whether the safety of the state
required such a step to be taken. If they decided in the affirmative,
a day was fixed for the voting, and each citizen wrote upon a tile or
oyster-shell [OSTRACON, whence the name OSTRACISM] the name of the
person whom he wished to banish. The votes were then collected, And if
it was found that 6000 had been recorded against any one person, he was
obliged to withdraw from the city within ten days: if the number of
votes did not amount to 6000, nothing was done.

The aristocratical party, enraged at these reforms called in the
assistance of Cleomenes, king of the Lacedaemonians. Athens was
menaced by foreign enemies and distracted by party struggles.
Clisthenes was at first compelled to retire from Athens; but the people
rose in arms against Cleomenes, expelled the Lacedaemonians, who had
taken possession of the city, and recalled Clisthenes. Thereupon
Cleomenes collected a Peloponnesian army in order to establish Isagoras
as a tyrant over the Athenians, and at the same time he concerted
measures with the Thebans and the Chalcidians of Euboea for a
simultaneous attack upon Attica. The Peloponnesian army, commanded by
the two kings, Cleomenes and Demaratus, entered Attica, and advanced as
far as Eleusis; but when the allies became aware of the object for
which they had been summoned, they refused to march farther, and
strongly protested against the attempt to establish a tyranny at
Athens. Their remonstrances being seconded by Demaratus, Cleomenes
found it necessary to abandon the expedition and return home. At a
later period (B.C. 491) Cleomenes took revenge upon De