Another explanation is that Virgil is thus indicating that what he has recounted is not to be taken as literal fact. In John Wesley's last sermon, preached on 17 January 1791, he spoke of how uncertain even the best conjectures about the invisible world were without revelation: "The most finished of all these accounts, is that of the great Roman poet. Where observe how warily he begins, with that apologetic preface, – Sit mihi fas audita loqui – 'May I be allowed to tell what I have heard'. And, in the conclusion, lest anyone should imagine he believed any of these accounts, he sends the relater of them out of hades by the ivory gate, through which, he had just informed us, that only dreams and shadows pass, – a very plain intimation, that all which has gone before, is to be looked upon as a dream!"