Plutarch, Dion
Bernadotte Perrin, Ed.

19. His arrival filled Dionysius with great joy, and the Sicilians again with great hope; they all prayed and laboured zealously that Plato might triumph over Philistus, and philosophy over tyranny. The women also were very earnest in his behalf, and Dionysius gave him a special token of his trust, which no one else had, in the privilege of coming into his presence without being searched. [2] The tyrant offered him, too, presents of money, much money and many times, but Plato would not accept them. Whereupon Aristippus of Cyrene, who was present on one of these occasions, said that Dionysius was safely munificent; for he offered little to men like him, who wanted more, but much to Plato, who would take nothing.

[3] After the first acts of kindness, however, Plato introduced the subject of Dion, and then there were postponements at first on the part of Dionysius, and afterwards faultfindings and disagreements. These were unnoticed by outsiders, since Dionysius tried to conceal them, and sought by the rest of his kind attentions and honourable treatment to draw Plato away from his goodwill towards Dion. And even Plato himself did not at first reveal the tyrant's perfidy and falsehood, but bore with it and dissembled his resentment. [4] But while matters stood thus between them, and no one knew of it, as they supposed, Helicon of Cyzicus, one of Plato's intimates, predicted an eclipse of the sun. This took place as he had predicted, in consequence of which he was admired by the tyrant and presented with a talent of silver. Thereupon Aristippus, jesting with the rest of the philosophers, said that he himself also could predict something strange. And when they besought him to tell what it was, ‘Well, then,’ said he, ‘I predict that ere long Plato and Dionysius will become enemies.’ [5] At last Dionysius sold the estate of Dion and appropriated the money, and removing Plato from his lodging in the palace garden, put him in charge of his mercenaries, who had long hated the philosopher and sought to kill him, on the ground that he was trying to persuade Dionysius to renounce the tyranny and live without a bodyguard.