Dion was anxious to give Syracuse a constitution, but he found Heracleides an incessant opponent in spite of the long forbearance he had shown him. Feeling that the one obstacle to a settlement must at all costs be removed, he yielded to advisers whom he had long withstood, and allowed them to put Heracleides to death. He gave him, however, a public funeral, and persuaded the people that it was impossible for the State to have peace on any other conditions.
But whence that sudden check?...
ἐτύγχανε μὲν γὰρ ὀψὲ τῆς ἡμέρας καθεζόμενος ἐν παστάδι τῆς οἰκίας μόνος ὥν πρὸς ἑαυτῷ τὴν διάνοιαν' ἐξαίφνης δὲ ψόφου γενομένου πρὸς θατέρῳ πέρατι τῆς στοᾶς, ἀποβλέψας ἕτι φωτὸς ὅντὸς εἶδε γυναῖκα μεγάλην στολῇ μὲν καὶ προσώπῳ μηδὲν Ἑριννύος τραγικῆς παραλλάττουσαν, σαίρουσαν δὲ καλλύντρω τινὶ τὴν οἰκίαν.—He happened to be sitting late in the evening in a corridor of the house in solitary meditation: suddenly a sound was heard in the further end of the portico, and looking up, he saw in the lingering light the form of a majestic woman, in dress and face like the Fury as she appears in tragedy—sweeping the house with a brush.
In Plutarch, the apparition is simply ominous of coming evil, his son, a few days afterwards, throwing himself in a fit of petulance from the roof of the palace, and his own death shortly following: the moral significance assigned to it in the poem is Wordsworth's own interpretation.
And, in their anguish, bear what other minds have borne!
In Plutarch, Dion calls his attendants, dreading to be left alone for fear the spectre should return (παντἀπασιν ἐκστατικῶς ἕχων καὶ δεδοικὼς μὴ πάλιν εἰς ὅψιν αὐτῷ μονωθέν τὸ τέρας ἀφίκηται). Wordsworth seems to have taken a hint from this passage, and to have added a tragic intensity by representing the horror as one which he could share with no one, a supernatural doom in which he must be absolutely solitary.
Ill-fated Chief! there are whose hopes are built
Upon the ruins of thy glorious name.
Callippus, an early friend of Dion's in Athens, and bound to him by a sacred association as he had initiated him into the mysteries, was now in Syracuse, and for selfish ends was plotting his friend's ruin, ἐλπίσας Σικελίαν ἆθλον ἕξειν τῆς ξενοκτονίας, 'hoping to get Sicily as the prize of his treachery.'