The spirit, Statius by name, who has just obtained his release from Purgatorial confinement to ascend to Heaven, states that the earthquake was not due to natural causes, such as strong dry vapors producing wind, but was caused by spiritual elements operative upon a soul's completing the penance and term assigned. * * * * * "It quakes here when some soul feeleth herself cleansed, so that she may rise up or set forth, to mount on high, and such a shout follows her. Of the cleansing the will alone gives proof, which fills the soul, all free to change her cloister, and avails her to will.... And I who have lain under this torment five hundred years and more, only now felt free will for a better threshold. Therefore didst thou feel the earthquake and hear the pious spirits about the mount give praises to the Lord." * * * * * This Statius was a Roman poet who died in the year 96. His term in Purgatory therefore has lasted a little more than eleven centuries. The next longest period mentioned by Dante is that of Duke Hugh Capet who has been in Purgatory over 350 years with his purification still incomplete. Statius by Dante's poetic invention is represented first as saved through the influence of Virgil's poems and then is shown to be a Christian, having been led to embrace Christianity both from the heroic example of the martyrs and from his meditation on Virgil's prophecy of the Cumaean Sibyl interpreted in the Middle Ages to refer to Christ. In the Divina Commedia Statius pays a glowing tribute to the AEneid and its author, wholly ignorant that he is addressing Virgil himself. "Of the AEneid I speak which was a mother to me and was to me a nurse in poesy ... and to have lived yonder when Virgil was alive, I would consent to one sun more than I need perform." Dante is all aquiver to surprise Statius with the information that Virgil is at hand, "but Virgil turned to me with a look that silently said, 'be silent.'"