History of the Genesis

This fragment is sculpted on only two adjacent sides and therefore was the cornerstone set between one of the jambs and the architrave of a portal. This was allegedly accompanied by a second relief with the initial part of the story set into the top portion of the other jamb.
The sculpture illustrates three episodes of the Book of Genesis: the story begins on the short side, where the Original Sin is depicted, then continues on the long side where one sees the Sacrifice of Cain and Abel and then Cain killing Abel.