Some time ago your Archive printed a paper on Greek mathematics which, in tone and style as well as in content, fell significantly below the usual standards of that journal. As it has already quite adequately (if perhaps too gently) been refuted there by V.D. Waerden and by Freudenthal, there is no need for referring to it by name. My only purpose in this letter is to point out that we have here almost a textbook illustration of the very thesis which the author (let us call him Z) sought to discredit, viz., that it is well to know mathematics before concerning oneself with its history; just as it is well to know Greek before dealing with Greek mathematics.