This article aims to reconsider the so-called ‘ἅπαξ δρώμενον criterion’, first introduced in Seminario Pots&Plays 2015; this principle refers to instances of mythological vase-painting whose content reflects innovative variations from extant V century BCE tragic texts. From a genealogical viewpoint, this coincidence parallels the philological principle of the ‘concordance in error’. We argue that this is the only relatively safe principle to ascertain any whatsoever connection between a drama whose text is known to us and a visual representation of its plot. The limits of this principle are first explored: sources pointing out to a unique dramatic version of a myth (as in Aeschylus’ Eumenides) may refer only to the works of the three gr...