In the Biblical book of Genesis, after Cain killed his brother Abel, Adam and Eve had a third son, whom they named Seth. Seth became one of the Patriarchs of the Bible, and was the ancestor of Methuselah, Noah, Jesse, David, Joseph, and Jesus. The possible subject of this window is Mahalalel, Seth’s great-grandson. The representation of Christ’s ancestors was a frequent theme in religious images, to reinforce the connections between the Old and New Testaments.