Under that date, he appears in the Roman Martyrology, the official but professedly incomplete list of saints recognized by the Catholic Church.

They depict Hermes as a wealthy freedman who with his companions was martyred in Rome, being killed on the orders of a judge named Aurelian.

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.

A pilgrimage in honour of the saint, who had by then become known for curing 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".