Je puis vous assurer, par mon expérience personnelle, que ce plaisir grec est peu agréable à cultiver.

Letter to his nephew, warning him against the vice of "pédérastie". From Les Matinées du Roi de Prusse. Quoted in Pisanus Fraxi, Centuria Librorum Absconditorum (1879), p. 411, note: "The authenticity of this work has been doubted, but M. Paul Lacroix has now swept away all doubt, and it must be acknowledged as being really from the pen of the great Frederick."