The epithet "Ποπάνων (Popanōn)" is attested only by Lydus, who cites Varro as stating that on the day of the kalendae he was offered a cake which earned him this title. There is no surviving evidence of this name in Latin, although the rite is attested by Ovid for the kalendae of January and by Paul. This cake was named "" but the related epithet of Janus could not plausibly have been Ianualis: it has been suggested "Libo" which remains purely hypothetical. The context could allow an Etruscan etymology.