Illuminating evidence. In the first century B.C., King Herod the Great built this 96-foot-long, 16-foot-high vault (and perhaps 100 more like it) as a huge storage complex for his port city Caesarea, on the Mediterranean Sea. In the third century A.D., this vault was converted into a mithraeum
, probably by Roman legionnaires stationed at Caesarea. The walls were plastered with elaborate frescoes, the 15-foot-high ceiling was painted blue and stone benches were added on the two long walls along with a stone altar at the terminus of the aisle.
At the eastern end of the mithraeum, a shaft of light pierces the ceiling. When this mithraeum was excavated, archaeologists noticed that the shaft of light moved each day, coming closer and closer to the altar. Just after noon on June 21, the summer solstice, the sunbeam reached the altar, flooding it with light. In keeping with Mithraism’s emphasis on celestial symbolism, the opening in the ceiling may have been intended to illuminate dramatically the central feature of the temple, at this pivotal date in the astrological calendar.