2. That of Eckhel, who thinks it possible that they may be intended to commemorate some wild freak of Gallienus, who may have thought fit to assume the attributes of the goddess Ceres, just as Nero and Commodus chose to be represented as divinities, the former as Apollo, the latter as Hercules. (Eckhel, vol. vii. p. 411.)
[W.R]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890