His existence in the 4th century is guaranteed by St. Athanasius, who includes him among the signers of the Council of Sardica in 343. His name also appears in the records of the pseudo-Council of Cologne of 346. St. Desiderius is third on the list of bishops of Langres (France). It seems he was a native of the area of Genoa and was miraculously appointed to the episcopal see of Langres. A clergyman of that city named Varnacarius wrote, at the beginning of the 4th century, a story of his martyrdom, basing it on local traditions. According to Varnacarius, the bishop Desiderius was beheaded during a Vandal invasion led by Chrocus. However, there was definitely confusion in the local traditions because Langres suffered numerous barbarian invasions and that of the Alamanni commanded by Chrocus (298-307) does not coincide with the dates of his stay as bishop of Langres. Therefore, it was probably the German invasion of 355-357, repelled by the emperor Julian the Apostate. One legend says that, following his decapitation, the bishop saint, like many other cephalophores, picked up his head and returned to the city, through a cleft in the rock that opened to let him pass. Said opening is shown still today. The cult of St. Desiderius of Langres definitely predates the 7th century and the Hieronymian Martyrology places his date on February 11th. However, in the 9th century, owing to a mistake made by a copyist and later perpetuated, confusion was made with Desiderius of Vienne, also remembered on February 11th, until it was decided to leave the saint of Vienne on this date and change the feast day of the bishop of Langres to May 23rd, date that was introduced in the Roman Martyrology once and for all. Moreover, the city of Langres also celebrates him on January 19th, anniversary of when the relics of St. Desiderius were transferred in 1315. His veneration was widespread not only in France but also Italy, Switzerland and Germany. He is the patron saint of Langres and many churches of the diocese are named after him. His tomb was preserved in a Benedictine priory located in the center of the city. In 1354, the brotherhood was established in his honor and counted kings and princes among its numbers. St. Desiderius was invoked as witness to the truth in oaths and as the protector during difficult childbirths.