Eumolpĭdae in Harpers Dictionary of Classical Antiquities（Εὐμολπίδαι). The most distinguished and venerable among the priestly families in Attica, believed to be the descendants of the Thracian bard Eumolpus, the introducer of the Eleusinian mysteries into Attica (Diod. Sic.i. 29; Apollod. iii. 15.4.) The ἱεροφάντης was always a member of the family of the Eumolpidae, as Eumolpus himself was believed to have been the first hierophant (Hesych. s. v. Εὐμολπίδαι; Hist. iv. 83). For the judicial powers of the Eumolpidae, see the article Eleusinia, p. 582.
Read More about Eumolpĭdae in Harpers Dictionary of Classical Antiquities