In Buddhism, you will hear people saying that a particular school's lineage can be traced all the way back to Shakyamuni Buddha.
That's 2,500 years or so. It sounds pretty impressive and perhaps lends a certain authority to the one making the claim ... and perhaps inspires credulity in the one hearing that claim.
And yet, for anyone who involves themselves in Buddhism in a serious way, if something can only be traced back to Shakyamuni Buddha, what kind of Buddhism would that be?
And further, if anyone could name a single thing -- anything at all -- that could not be traced back to Shakyamuni Buddha, I'd be more than willing to give them a nickel.
OK, I can see the point of tracing this and tracing that. It's helpful in a small way. But I do get tired of hearing people say that a school or teacher or true teaching goes all the way back -- but no further -- to Shakyamuni Buddha.
It strikes me as a kind of nickel-and-dime, Tupperware kind of Buddhism.