Again at the beginning of the Second World War, the monk and artist Radbod Commandeur from the Benedictine Abbey of Maria Laach created the large apse mosaic, which dominates the interior view of the upper church.
Four pairs of Old Testament prophets announce the birth of the Messiah. Their message culminates in the promise of the prophet Isaiah:
Therefore the Lord himself will give you this sign: the virgin shall be with child, and bear a son, and shall name him Immanuel (God with us).
The promised Son sits enthroned on the arm of his mother and announces with an open book:
I am the light of the world.
The marble slabs, which were planned as facing for the lower part of the apse, could not be transported from Germany to Palestine because of the war and were destroyed by bombing together with the Cologne Spedition, where they were stored.
The apse mosaic thus remains incomplete.