Philo Judaeus In Flaccum 9

[9] But in the last year, after Tiberius was dead, and when Caius had succeeded him as emperor, he began to relax in and to be indifferent about everything, whether it was that he was overwhelmed with most heavy grief because of Tiberius (for it was evident to everyone that he grieved exceedingly as if for a near relation, both by his continued depression of spirits and his incessant weeping, pouring forth tears without end as if from an inexhaustible fountain), or whether it was because he was disaffected to his successor, because he preferred devoting himself to the party of the real rather than to that of the adopted children, or whether it was because he had been one of those who had joined in the conspiracy against the mother of Caius, having joined against her at the time when the accusations were brought against her, on account of which she was put to death, and having escaped through fear of the consequence of proceeding against him.