The Rosicrucians claim to be directly descended from Atlantis (their teachings, at least), which is a pretty mystical and far-fetched claim (where my own personal conviction is that John Dee may have been the founder of Rosicrucianism, either directly or indirectly, but more than likely influenced it if he was not). Some people argue Enochian is the language that was used in Atlantis. As far as I'm aware, Atlantis was an invention of Plato, but feel free to correct me on that. Likewise the Golden Dawn claimed to be a continuation of the old Rosicrucian movement in Germany and had Cipher Manuscripts and letters from Anna Sprengel to "prove" it - the Ciphers turn out to be real (albeit not as old as they were claimed to be), but the letters are an obvious, if understandable, forgery. Qabalah claims that its texts, predominantly from the Middle Ages, originated a good 1,000 years before that (and I would argue that there is a strong oral tradition in Judaism and thus it's likely the teachings are older than the texts, but that's it. It's "likely", not fact). Then there's the Christian and Gnostic gospels - all written way after the apostles would have died, yet predominantly claiming to be written by them. And these happens with Hermetic texts also, claiming to be written by or taught by Hermes Trismegistus, who is at the end of the day a mythical figure.
The point I'm trying to get at here is that nearly every tradition makes up an older origin to give it credence. If a prophet of Dublin was to get crucified and I was to claim to have been given a book written by one of his disciples, there'd be a stir. If I admitted that I wrote it myself no one would read it, even if it contained the actual teachings of this prophet, even if it's in the same style and tradition. People seem to think that "older" equals "more true". Is that necessarily the case?
I once argued this with someone who claimed that Hermeticism was the oldest thing in existence (I love Hermeticism, but come on). I pointed out Gnostic links in the Corpus Hermeticum and he said that he taught the Corpus Hermeticum wasn't very Hermetic. For anyone who's even vaguely familiar with this topic, I think the Hermetic nature of the Corpus Hermeticum is fairly evident. Indeed, that's where the term comes from, and that's one of the oldest sources we base our knowledge of Hermeticism on (stemming from the same time and place as the height of Gnosticism, which is probably why the Gnostics of Nag Hammadi had Hermetic texts in their library). Instead this guy argued that the Kybalion is what he saw as more Hermetic. I pointed out that it was roughly 100 years old and he tried to backtrack.
Ancient Alexandria was a hot-spot for many different traditions. It was the centre of a deep philosophical and esoteric "mingling", where ideas were given and absorbed, and this is the place where Gnosticism saw its peak. Indeed, this is also the place where we get the Hermetic Corpus from. And, let's not forget that the name "Hermes" is a Greek name. Hellenistic Greece was a mixture of Greek and Egyptian (and Jewish, for that matter), and Hermes Trismegistus is a mixture of Hermes (the Greek god) and Thoth (the Egyptian god). Even the language of Coptic, which so many of these texts were written in, was Egyptian written in Greek. It was, in my opinion, almost inevitable that new traditions representing bits and pieces from other ones would arise from this meeting and merging of paths. The two dominant ones I can see from this era are Gnosticism and Hermeticism.
Thus, I propose that these are actually sister traditions, and come from a common stream, which is why it's so easy to inter-relate the two, why both seem to espouse and support each other's teachings. In a sense, the Hermeticists did exactly what the Gnostics did, but decided to do it devoid of Judaeo-Christian mythology (in much the same way as the Jewish Gnostics tried to omit any reference to Christian mythology).
This kind of "everything started in Ancient Egypt" argument is, I believe, sorely lacking, yet more and more people seem to use it without understanding much about it or where it came from. There are many who claim Christ was taught by a priest of Osiris, for example, and various other "it goes back to Egypt" claims. While some of these might be true, we need to make the necessary distinction between what may be and what is. The Hermeticism/Hermetism of Ancient Egypt might have been. The Hermeticism we know today is, and just because it's only 2,000 years old doesn't make it any less beautiful and valuable and true.