10 October - Born in Greece at the beginning of the 7th century, Ghislain comes from a Gallic or Belgian family. After studying literature in Athens, he joins the order which applies the rules of Saint Basil and is ordained a priest. He would have been the archbishop of Athens.

Ghislain lived in Rome to visit the tombs of Saints Peter and Paul. In 648, the Pope sent him to Belgium with Saint Lambert and Bellère, and in Maastricht he met and befriended Saint Amand. Ghislain wanted to live the life of a hermit. He lived by the riverside, where he had built a small house for his disciples and himself. He built a monastery in the town of Ursidongus. Ghislain's mission had a negative impact on Albert, bishop of Cambrai, and he was summoned and questioned: "I am Greek and Christian. I was born in Athens and I was born a second time through the baptism of Jesus Christ. I was in Rome, and by divine order I came to this city, Ursidongus, I worked with my hands and I wanted to build a place of worship in honour of Saint Peter and Saint Paul, asking your permission to continue". There, the Pope took Ghislain under his protection and his church was blessed with 653. Many followed Ghislain's spirituality, including the sisters Aldergonde and Waudru. Ghislain died in 658, and was buried in the church of the monastery he built, where he performed many miracles. His veneration began in the 9th century.