I ran across these while looking for something else, and it occurred to me that this is a good example of how the carved scenes inside the "skulls" rosary we've been looking at might look if they were removed from the skulls.
However these four medallions are ivory, rather than wood. They were originally painted in bright colors, as were most medieval ivories. The plain white appearance of so many ivories today comes from natural wear and from over-cleaning in the 19th century, due to that century's preference for "pure" sculptural forms untainted by color.
While not a lot of German is needed to navigate the Marburg archive, there are certain terms that are useful in reading the museum labels, including the names for various materials, such as "Holz" = wood, "Buchsbaum" = boxwood, "Bergkristall" = rock crystal, and the current "Elfenbein." The word "Bein" means "bone, and for a long while, every time I saw "Elfenbein" it irresistably suggested "elf bones." Actually it's elephant bone, that is, ivory.
These medallions do look as though they come from a set, similar to those in the skulls. The first two are scenes of St. George and St. Catherine of Alexandria. St. George has his spear, his dragon (underfoot), his horse, and at left, the princess he's rescuing. St. Catherine is identifiable because she's holding in one arm a pie-shaped segment of a wheel (you can easily see the three spokes and segment of rim), a symbol of her martyrdom.
The other two medallions in the set are incidents from the life of Christ: the Crucifixion at left, and at right the appearance of the Risen Christ to the women at the tomb.