Every time I read on some historical figure or other, I always end up checking out their children and their children's children, but it always ends in a couple sentences of mayhaps and possiblies. Made harder because inevitably, someone had a daughter, and no one wrote about them unless they married somebody important.
Is there a family line we can reliably trace from a well known ancient figure? Ceasar or maybe one of the Chinese dynasties? And how did we manage to do that, since record keeping seems to have been spotty?
The "Confucius Genealogy Compilation Committee" maintains a family line for, you guessed it, Confucius, going along the main line of descent. As Confucius lived from the 6th-5th century BC (and the line actually goes back a bit further than Confucius), this is a very ancient line to say the least. I'm not really sure what records they are working with, though.
How about the 18th dynasty of Egypt? It's somewhat easier in Egypt, since it was a continuous culture for so long, and the 18th dynasty was the height of the new kingdom (it included king tut). I don't think its necessarily that record keeping was spotty, but many invaders burned libraries and record houses, and over time there seemed little purpose in keeping lineage records around if they were not important for some reason. Even in Egypt, Pharoahs stole from the graves of Pharoahs who they weren't directly related to.
hi! this question might be more up the street of /r/genealogy, but you may be interested in a few discussions in this sub