Fragment of an ivory diptych
The Louvre
The middle of this piece represents the rarely illustrated episode of the water test (chapter 16 of the Protevangelium of James and chapter 12 of the Gospel of Pseudo-Matthew): the high priest disbelieves Joseph and Mary's explanation of her pregnancy, so he has Joseph drink "the water of drinking of the Lord," which would cause a sign of his mendacity to appear on his face. When no such sign appears, Joseph is acquitted. Then Mary is tested in the same way and also acquitted.