Larry J. Kreitzer, «The Plutonium of Hierapolis and the Descent of Christ into the 'Lowermost Parts of the Earth' (Ephesians 4,9)», Vol. 79 (1998) 381-393
After a general discussion of the myth regarding Demeter, Persephone and Hades/Pluto, the author discusses, in the light of coins of the early Neronian period (54-59 AD), the likelihood that the Plutonium of Hierapolis is the geographical spot the author wants his readers to imagine when they read in the Letter to the Colossians that Christ entered the lowermost parts of the earth.
connection of the site with the story of the abduction of Persephone and that he wished to present the Christian message as somehow challenging, or transcending, the mysteries associated with the local expression of the Demeter/Persephone cult. We can also assume that he would have known of the identification of Demeter with Cybele, and that the cult of Cybele and Attis would have been familiar to the local population, given that this was originally a Phrygian religion and both Colossae and Hierapolis were in Phrygia. In short, what we have in Ephesians 4,9 may be an instance of the direct engagement of Christian thinking with the popular religious myths which prevailed in the Lycus valley. Perhaps there was even within the church at Hierapolis a need for an apologia along these lines as those new to the faith were attempting to move from pagan darkness into the light of Christian truth, from childish obsession with empty myths to full maturity in the faith (see 2,1-7; 4,11-14. 17-18; 5,6-14). This unknown disciple of Paul thus makes a christological assertion about the power of the risen Lord who holds the keys to life and death, who has descended into the very bowels of the earth and has returned to claim the city of Hierapolis in triumph 38.