Guilielmus de Malavalle
Guilielmus (Dutch: Wilhelmus; English: William), duc of Aquitania and count of Poitiers, supporter of anti-pope Anacletus II, converted by Bernardus of Clairvaux. He withdrew himself in Malavalle, an isolated valley in Toscana, Italy, to live a hermit's life. He died in 1157, and was canonized in 1202. After his death his followers founded the Wilhelmietenorde.
- natalis: 10 February
- translation: 4 July (Baseldonck)
An office for him is preserved in the antiphoners NL-Avu xv 05006 and NL-Avu xv 05007 of Baseldonck in 's Hertogenbosch; see for an edition the contribution of Hans Smolderen in Gregoriaans in laatmiddeleeuws 's-Hertogenbosch, pp. 111-160, espec. pp. 126-133.
An office is preserved in mss of the Wilhelmietenklooster in Walincourt near Cambrai too.