Oh, I know about those Usenet speculation origins of the "13 Dark Lords". What I've wondered for some years now is to what extent (if any) it may have influenced actual EU works. One still sees mention of it from time to time, and back in the day some authors must have at least been aware of it. As for the quote of "long dormant", it's from the original Essential Guide to Characters: That bit about "tens of thousands of years" is also meshes well with another remnant of the earlier EU bit in that the Sith originated from the First Great Schism circa 25,000 BBY, near the dawn of the Republic. While this did get changed to the later 6,900 BBY date in the 2005 New Chronology, a lot of works in between that and the first Characters Guide were written on the assumption that the Sith had actually emerged from the renegade Jedi of the First Schism.