This essay analyses a programmatic passage of Seneca the Elder’s Controversiae book x, in which Seneca explains why he uses Greek quotations as well as Latin in his work. The transmission of the text has been suspected of corruption, but the comparison with Seneca’s general approach to Greek declamation suggests that the lectio tradita ought to be maintained. By quoting altogether Greeks and Romans, Seneca aims both to show the non-inferiority of the Latin declamation, and to underline important differences in freedom of expression between Greek and Latin.