Cassius Dio 69.19.2 (tr. Earnest Cary):
Moreover, he assumed the command of the Praetorians reluctantly, and after assuming it resigned it. Having with difficulty secured his release, he spent the rest of his life, seven years, quietly in the country, and upon his tomb he caused this inscription to be placed: "Here lies Similis, who existed so-and‑so many years, and lived seven."
καὶ τὴν τῶν δορυφόρων ἀρχὴν ἄκων τε ἔλαβε καὶ λαβὼν ἐξίστατο, μόλις τε ἀφεθεὶς ἐν ἀγρῷ ἥσυχος ἑπτὰ ἔτη τὰ λοιπὰ τοῦ βίου διήγαγε, καὶ ἐπί γε τὸ μνῆμα αὑτοῦ τοῦτο ἐπέγραψεν ὅτι Σίμιλις ἐνταῦθα κεῖται βιοὺς μὲν ἔτη τόσα, ζήσας δὲ ἔτη ἑπτά.