GUGLIELMO di HIRSAU, Blessed. — A Bavarian, he died on 4 July 1091 at Hirsau. As a child he was offered as an oblate to the monastery of S. Emmerano at Ratisbona; in 1069 he was called by the monks as abbot of the restored Hirsau, yet he did not allow himself to be ordained before the death of his predecessor Federico, who had been unjustly deposed. Under his prudent and moderate government, Hirsau began to flourish again. G. worked tirelessly to obtain from Enrico IV and from Pope Gregorio VII, whom he personally visited, full exemption for his monastery, which he governed until 1075.
Following the model of the Constitutiones Cluniacenses, he composed the Constitutiones Hirsangiennes (cf. M. Fischer, Studien zur Entstehung der Hirsauer Konstitutionen, Tubinga 1910). The number of monks grew so greatly as to make the construction of another monastery necessary (1083–92), and numerous monastic colonies could be sent to Erfurt, Magdeburgo, Stiria, and Carinzia. He was one of the promoters of the Institute of Oblates within the Benedictine Order. After his meeting with Pope Gregorio VII and the visit of the latter’s legate Bernardo di Marsiglia, G. and his monks became vigorous defenders of the Gregorian reform in
Germany. He was a man of good learning and left several works: Dialogi de Musica (PL. 150, 1147–78; critical edition by H. Müller, Francoforte 1883) and Astronomia (only the prologue printed: PL 150, 1639–42). Until the decline of the monastery of Hirsau, G. enjoyed public veneration. Feast day: 5 July.