The Return of Persephone, 1891, Frederick Leighton, page 200 in your fine art book You and the Universe. Demeter welcomes her daughter, guided by Hermes carrying his caduceus in his right hand, back from Hades. Hades/Pluto tricked Persephone into eating three or six (tales differ) pomegranate seeds while she was in Hell. For each one she ate she had to remain in Hell as Hades' queen one month out of every year.