History of the Peloponnesian War

Their hearts failed them because they thought the conspirators more indeed than they were; and to learn their number, in respect of the greatness of the city and for that they knew not one another, they were unable.

For the same cause also was it impossible for any man that was angry at it to bemoan himself, whereby to be revenged on them that conspired; for he must have told his mind either to one he knew not or to one he knew and trusted not.