As against this, the coincidence is explicable if one remembers that the figure who appears to Munthe also claims to have appeared centuries previously to none other than Tiberius. It has always been assumed that Munthe invented this genius loci; but what, it occurred to me, if he had not? Might not such a supposition confirm the authenticity of the memoirs?

Then there is another story – about Sirens – which recalls one by Giuseppe di Lampedusa. That would place the concoction of the memoirs unacceptably late, I thought; besides, the Mediterranean lands are rich in Siren stories, and it is known that Tiberius took a particular interest in the myth. And then there is the postscript, which is decidedly rum, though it purports to account for the survival of the original memoirs in manuscript.

Ultimately I remain undecided. I do not assert that these are the memoirs of Tiberius, or not unequivocally so. I think the bare bones of the narrative may be authentic, but that subsequent versions have refined, expanded and glossed them.

And I find myself asking whether it matters. What we have here, persuasively and movingly in my opinion – else I should not have put myself to the labour of translating the work – is a remarkable portrait of one of the greatest, and certainly the unhappiest, of Roman emperors. In the end, I say to myself, fiction – if this is fiction – may offer truths to which neither biography nor even autobiography can aspire. Who knows himself or another man as thoroughly as the artist may imagine a life? Whose identity is fixed? A great and malignant artist, Tacitus, pinned a terrible portrait of Tiberius on the wall of history. If another hand has been moved to amend that picture, so be it. It was Napoleon, with his uncanny penetration of men's motives, who dismissed the great historian as le poete; yet Tacitus' lying truth held sway for centuries. The author of this autobiography, whoever he may be, is, I would claim, a poet himself at moments, and I trust that his version of the story, a version which is certainly the case for the defence, will work its influence also.