Johanniter-Kommende "Heilig Grab"

The Johanniterkommende was founded in 1281. It is believed that the building may have been taken over from the Canons of the Holy Sepulchre, with the Holy Spirit Chapel dating back to the 12th century. Between 1306 and 1502, the commandery oversaw the branch in Hangen-Weisheim, and from 1325 to 1367, the Worms branch was affiliated as a part. The current buildings were erected between 1740 and 1748 on the site of a former Gothic residential tower. Following the dissolution of the Order of St. John during secularization in 1803, the building housed an artillery school under Napoleon from 1813 to 1814. Subsequently, it served as the engineering directorate of the Mainz Fortress until 1918. Between 1930 and World War II, it was used by Franciscans. The side wings suffered severe damage during air raids in 1945 and were restored starting in 1954. The commandery's chapel was demolished in the 1960s, but its three-conch choir foundations were rediscovered before 1998.

The monastery is located at Bischofsplatz 2 in the old town of Mainz, a city in Rhineland-Palatinate, Germany.

The building is now owned by the Diocese of Mainz and has housed the Episcopal Ordinariate since 1969. The Baroque architecture, designed by Johann Caspar Bagnato and Anselm Franz von Ritter zu Groenesteyn, features classical elements with a central main building, a triangular gable, and two projecting pavilions. The Maltese cross and the Mainz wheel are depicted as an alliance coat of arms in the gable. A wrought-iron gate with chain-draped cannonballs and flames, allegorical to the French artillery school, delineates the ensemble from the street.

• Episcopal Palace (sacred building, approx. 67 m away)
• St. John's Church (sacred building, approx. 84 m away)
• Palais Älterer Dalberger Hof (residence, approx. 178 m away)
• Mainz Cathedral (sacred building, approx. 188 m away)