William was born of a noble French family and educated by his uncle Hugh, forty-second abbot of Saint-Germain-des-Prés at Paris, and, having been ordained subdeacon, received a prebend in the church of Sainte-Geneviève-du-Mont.
[1] William reportedly sought entry into a stricter house (either a Cluniac or a Cistercian monastery) while still in his youth, though he decided to remain at Ste-Geneviève.
According to the hagiographic sources, his exemplary life did not commend him to his fellow canons, who tried to rid themselves of his presence, and even prevented by slander his ordination to the diaconate by the Bishop of Paris.
[2] Such actions apparently put William at odds with his abbot, who subjected him to humiliating discipline, about which the canon complained bitterly to the pope.
In 1161 Absalon, bishop of Roskilde (and later archbishop of Lund) in Denmark, sent to Paris the provost of his cathedral (almost surely the Danish historian Saxo Grammaticus) to obtain canons regular for the reform of the canonry of St. Thomas at Eskilsø.
Nevertheless, despite difficulties arising from poverty and opposition on the part of the community, he reformed the monastery[1] and in 1176 transferred it to Æbelholt, dedicated to the Paraclete, in Sjælland (now Region Hovedstaden), near the present-day town of Hillerød.
As abbot, William worked to institute the standards of religious discipline emerging from reform centers in the heartlands of Latin Christendom.
These included other communities in the Augustinian tradition (such as Vestervig), but also extended to Cistercian houses, most notably the monks of nearby Esrum Abbey.
[5] Numerous miracles were reported at his grave, and in 1218 the Archbishop of Lund, Anders Sunesen, requested that Pope Honorius III appoint a local commission to investigate the claims for William's sanctity.
Then, in January 1224, William was canonized by Honorius,[6] who acted on additional information provided by Cardinal Gregorius de Crescentio, recently returned from a papal legation to Denmark.