How did Ancient Greeks know that the liver is capable of regeneration?

by ChemicalBeyond

In the story of Prometheus, he is chained to a rock and an eagle eats his liver everyday. Did ancient greeks have advanced enough understanding of the human body to be capable of knowing that the liver regenerates?

jelvinjs7

More can be said if someone has something to add, but /u/timadjani goes into that in this answer:

According to Greek myth, Prometheus had his liver eaten by an eagle everyday only for it to regenerate at night. Did we know centuries ago that the liver is the only organ that can regenerate?