This wall painting is a 15th century 'memento mori'. The story goes that 3 kings were travelling through a forest when they happened upon 3 skeletons. The skeletons told them 'As you are now, so once were we. As we are now, so you will be.' The kings ran away but were killed in their beds that night.
The paintings had been whitewashed over as they were not all religious scenes and were uncovered in the early 20th century. The kings crumbled away with the wash but the skeletons remained as they still do today.
