Since the 5th century, Saint Stephen and the Virgin Mary have been worshiped on Mont Sainte-Croix. Only the sanctuary, dedicated to Saint Stephen, was preserved from the attack of the Huns in 451. From then on, its reputation increased in the region and the Christian world. When the idea of building a cathedral emerged in Metz, it became undeniable that it had to happen in this location. Its foundations rest on those of the sanctuary, and they both share the same crypt, containing the royal treasure.