I can answer the question in part, at least. My knowledge of such a thing is limited to Mesopotamia, and so there may or may not be an answer more fitting from elsewhere. My inclination is that you answer, though, does indeed lie (as it were) somewhere in this region.

The Royal Tombs of Ur (excavated by C. Leonard Woolley in the 20's and 30's) date to at least the 24th century BC. There are markings on the graves that are all-but-certainly meant to convey the identity of the interred, but who exactly is being identified is unclear to us today.