Workman digging in a field near Dormagen (Durnomagus) found a vault in which there was a chamber ten feet high, ten feet board and forty week long. Peter Delhoven, a prominent collector of Roman artifacts, particpated in the excavation of the mithräum. The interior walls still had evident traces of green and red paint on the walls.
Against one of the walls were found two monuments. The first monument was 2 1/2 feet high and two feet wide. It was made of limestone. Mithras and the bull depicted on the relief were damaged.