[informatimago]

Indeed. 500 years is about 16 generations, so any ancestor of that age may have 65536 or even more descendents. You'd need to locate them and ask them all permission. How does it work, is it majority vote? Unanimous vote?

All European people have a unique male ancestor 300 generations away. If you locate remains of that age, do you have to ask nobody or everybody? (Depending on whether it's the male ancestor of all of us, or some other male whose last descendent died long ago?)

[samus]

Human societies have elaborate processes to solve this issue: inheritance laws. In case no heirs can be located anymore (body can't be identified, records are missing, the line has died out, etc.) the state is the heir by default and makes the rules.