Stabbed by night by a monk he had himself baptised, he sent him to Rome to be forgiven.
Born about 636 into the aristocracy of Aquitaine and trained at Reims by Archbishop Nivard, he went to become a monk at Luxeuil, in the Columbanian tradition. Back in Champagne, he persuaded Nivard to found Hautvillers and was its first abbot, then went deep into the forest of Der to build, about 670, the monastery that would become Montier-en-Der. He added to it a house for women at Puellemontier, and made the journey to Rome and the Holy Land from which he brought back relics. A monk of his community named Daguin, whom he had himself baptised, took a reproof badly: he entered his cell by night and stabbed him. Bercharius lived two days. His murderer was brought to him; he addressed him no complaint and no reproach — he asked him only to do penance and to go to Rome for absolution. It is that trait, reported by his Life, which caused him to be venerated as a martyr, though he did not die for the faith. His Life was written three centuries later by Adso, abbot of Montier-en-Der; the abbey he had founded lasted until 1790.
An abbot in dark habit with crozier and book; sometimes the dagger of his murder, or a model of his abbey.