His existence is attested by his early cult. However, his Acts, included in those of Pope St. Alexander I, are legendary. They state that Hermes was a martyr with companions in Rome, who were killed at the orders of a judge named Aurelian. Hermes was a wealthy freedman.
Some of his relics were given to Spoleto by Gregory the Great. Other relics went to Lothair I by Pope Leo IV; Lothair brought them first to Cornelismünster, near Aachen. The relics later came to Ronse in the 9th century. During those times, Viking raids forced the monks to flee the town more than once, and the monastery was burnt by the Normans in 880. The relics were recovered in 940 and housed in a Romanesque-style crypt in 1083. The church of Saint Hermes, which was later built on top of the crypt, was consecrated in 1129. A pilgrimage in honour of the saint, who had by then be known to cure mental illnesses, sustained the local economy. There is still a French saying today which translates as "Saint Hermes cures the area's madmen but keeps the Ronse dwellers as they are".
In past centuries, St. Elmo's Fire was sometimes called "St. Hermes’ Fire.
Although he is recognized as a saint of the Roman Catholic Church, the commemoration of Saint Hermes in the Roman Catholic calendar of saints was removed in 1969 (as usual, ed.) because of the paucity of information about him.