[2] He resigned and went on a pilgrimage to Rome[3] in a group that included his deacon, Saint Reinfroid.

On their return they passed through German lands and then south of the Vosges, near today's Saint-Dizier-l'Évêque[4] and was welcomed in the local church.

Having preached there, he went on the road again but was soon attacked by robbers who killed him and his acolytes near the village of Croix, Territoire de Belfort.

[5] Didier was buried in the church and a cult arose around him as is attested in a 727 charter in Murbach Abbey.

[3] A rock named "The step of the devil and the feet of Saint Didier", found near Saint-Dizier-l'Évêque, has indentations that local legend claims are the remains of a struggle between the devil and the saint.