Aeginetans, more jealous than themselves, and the astute and
proverbial sagacity of the Spartan council--it is impossible to
believe that, for so long a period as, with the greatest expedition,
must have elapsed from the departure of Themistocles to the necessary
progress in the fortifications, the ephors could have been ignorant of
the preparations at Athens or the designs of Themistocles. I fear,
therefore, that we must believe, with Theopompus [120], that
Themistocles, the most expert briber of his time, heightened that
esteem which Thucydides assures us the Spartans bore him, by private
and pecuniary negotiations with the ephors. At length, however, such
decided and unequivocal intelligence of the progress of the walls
arrived at Sparta, that the ephors could no longer feel or affect
incredulity.

Themistocles met the remonstrances of the Spartans by an appearance of
candour mingled with disdain. "Why," said he, "give credit to these
idle rumours? Send to Athens some messengers of your own, in whom you
can confide; let them inspect matters with their own eyes, and report
to you accordingly."

The ephors (not unreluctantly, if the assertion of Theopompus may be
credited) yielded to so plausible a suggestion, and in the mean while
the crafty Athenian despatched a secret messenger to Athens, urging
the government to detain the Spartan ambassadors with as little
semblance of design as possible, and by no means to allow their
departure until the safe return of their own mission to Sparta. For
it was by no means improbable that, without such hostages, even the
ephors, however powerful and however influenced, might not be enabled,
when the Spartans generally were made acquainted with the deceit
practised upon them, to prevent the arrest of the Athenian delegates.