Valerius Maximus, Memorable Deeds and Sayings 8.7.ext.13
Simonides vero poeta octogesimo anno et docuisse se carmina et in eorum certamen descendisse ipse gloriatur. nec fuit inicum illum voluptatem ex ingenio suo diu percipere, cum tantam omni aevo fruendam traditurus esset.
Simonides the poet himself boasts that in his eightieth year he both led rehearsals of his poems and entered a poetic competition. It was not unfair for him to take that delight in his genius for so long, since he was to hand on such great enjoyment to all future ages.