Built: 2nd to 3rd century AD

Roman legionnaires brought the cult of Mithras to Mainz as early as the 2nd century AD: it competed strongly with the emerging Christianity, as both religions had many similarities.

The cult meeting rooms, known as mithraea, were located underground and consisted of elongated vaults with a Mithras altar at the front. The vault was painted to resemble a starry sky. The followers of the cult therefore only appeared to descend underground; in reality, they gathered under the canopy of the heavens.

The well-preserved altar is made of Odenwald marble. Its original inscription, written in red, reads: "Secundinius Amantius, chief clerk of the legion prefect of the XXII Legion, had this stone erected in fulfillment of a vow to the undefeated sun god Mithras and Mars."

The second altar, made of Flonheim sandstone, is badly damaged. However, its inscription – although very weathered – also links it to the cult of Mithras.

The remains of the two consecration altars are located in a covered passageway on the ball court and can be viewed at any time.