History is written by the victors if they live long enough. You want an example that demonstrates brilliantly just how self-contradictory, not to mention heaped with layer upon layer of subsequent societal bias, and thus demonstrably full of you-know-what, the record can be? I refer you to the history of Alexander the Great. It is now possible for two historians of equal repute to make equally well-documented arguments that Alexander was a) a raging drunken megalomaniac tyrant and b) a brilliant noble civilizing hero. The academic "party line" on this question has swung drastically within living memory. So what do I rely on for the real picture? What else have I got? Memory! (Several people's, not just mine. That way I can balance my own naturally self-serving bias with others more critical, i.e. present all the versions and let the reader judge.)
That said, or perhaps I should say ranted. I think you can certainly use the historical record to make a convincing argument that you are somehow remembering or accessing knowledge of a previous time, whether you lived then or you're doing remote viewing through time or whatever. (Apparently remote viewing can be done through time as well as space, which could throw a wrench into any and all past life claims, I suppose, if the skeptic believes in remote viewing, that is! I personally think that past life memory and past remote viewing both happen, and that could be an explanation for multiple claimants for the same past lives, simultaneous lives being lived by the same soul, etc. Could be. I absolutely claim no certainty here!)
Anyway, I think the best test satisfies these requirements:
1) The information is truly verifiable, e.g. memories of the appearance of places which still exist and are known not to have changed, events which are agreed on even by opposing sides of a historical debate or are mentioned in so many sources as to be irrefutable, etc.
2) There is no way the claimant could have learned the information before, even by having flipped through a book or flashed on a website -- since the mind is capable of remembering details even seen for a moment; so here, to be absolutely certain, you want verification of details that are only historically available somewhere the claimant has never been able to access.
3) The random chance factor is eliminated, i.e. the memories are correct on more details than could be accounted for by chance.
Even satisfying all these, I myself wouldn't necessarily believe I'd lived a given past life without other evidence such as similarities, connections, and continuities between the current life and the past one -- lots of them. When I say lots, I mean hundreds (including the subtle ones). I wouldn't believe I'd lived a past life without it providing the answer to some burning questions of this life. But this sort of test is what convinces outsiders. For a very well-done job of it in book form regarding a famous past life, read Donald Norsic's To Save Russia. Nor would I disbelieve in a past life if it doesn't satisfy all of these requirements, since in many cases -- such as a life about which no facts are irrefutably known -- that simply isn't going to be possible.
This next idea of mine I wrote about on another thread: a claim of two famous past lives offers a unique opportunity: an examination of the historical record is likely to show up similiarities, connections and continuities between the two lives. The beauty of this is that it is completely independent of the claimant, especially if the historical material was extant before he was born; the only input of the claimant is to say that the two lives were lived by the same soul, which can then be tested for historically, looking for the sort of similarities we know of from the many this-life/past-life comparisons we've all read. Of course to eliminate the possibility of cryptomnesia, it's also required that the claimant not have read enough on the two lives to have spotted similarities before having made the claim, as otherwise that might have inspired it.
The only example I have is my own, re Alexander and Thomas More, and so far I've focused mainly on More's book Utopia, since I know from my this-life experience that writers of imaginative works can unknowingly be inspired by past lives. Well, in Utopia (which was extant, of course, more than 450 years before I was born) More drew from many sources, but there is a strong current of Alexander under the surface. Example: by linguistic clues that More himself comments on (p. 84 in my edition), Utopia seems to be akin to a successful fusion of Greek and Persian culture, with Greek the more recent addition. The only person in history who ever actually attempted to fuse those two cultures was Alexander. Another example: the similarities of the "conqueror" of the island, after whom it is named -- Utopus -- to Alexander are many, including even the way he names it: Utopia from Utopus, Alexandria from Alexandros. Another example: Utopia's military strategies and policies are in many ways identical to Alexander's. Now you could argue that More was a classical scholar and therefore perhaps knew these things from his education and decided to use them. But why did he choose so many? (I've mentioned only some. I don't think I've even got them all, because I don't have enough expertise; for instance, I know that some scholar spotted some implicit references to the Iliad, Alexander's favourite work, in Utopia but I haven't found them yet.) And if More admired Alexander and followed him consciously, why didn't he say so, as he did with numerous other classical figures mentioned?
For me to have claimed the two lives due to having been inspired by these similarities, I would have had to read Utopia before any memories came up, which, as I recall, I didn't, and to have studied Alexander history in some detail, which I also didn't, and to have connected the two, delineated the similarities, and decided that they were enough to make a claim, all subconsciously... but not only that. I would also have had to decide not to pick, as another notable life to add to Thomas More in my quest for bragging rights, one of the classical figures he names in Utopia, one of which in particular seems more directly connected (Plato, author of The Republic). I would have had to recognize subtle similarities to a past life in a piece of literature before I learned what these similarities look like through spotting them in my this-life writing. Now I know the cryptomnesiac mind can do some amazing work, but this seems a stretch even for it.
Is that validation? Well, validation is like beauty, it's in the eye of the beholder. I know that I myself have needed a lot of other evidence as well as this to be even majorly convinced (and I'm not 100% convinced to this day). But I will say, I think historical verification is worth a shot, so long as the history is on firm ground. Last point: the more recent the life is, the easier it is to find its historical traces, as less time has passed to erase them.
Love & peace,
Karen