The vault of the Mithraeum is stuccoed and decorated with stars. These are painted inside a circle, they each have eight rays and they are alternately red and blue on a dark-yellow background. In the center of them a very small hole is often visible. It is said that when it was discovered the vault was besprinkled with precious stones which were later on stolen; but among the loose earth we found a little circular piece of blue glass paste with a hole in the middle; it therefore seems probable that these glass decorations (which may have been of various colours) were nailed into the stars. Yet…