By Lorris Chevalier
Between its foundation in 910 and its apogee in the 12th century, the Abbey of Cluny stood as the most significant monastic center of medieval Europe. The third and final church of the complex, Cluny III, constructed between 1088 and 1130, was the largest religious building in Christendom until the completion of St. Peter’s Basilica in Rome in 1510. The origins of this ambitious architectural endeavor were deeply rooted in a vision—one received by Gunzo, a retired abbot of Baume, who, in his final days, experienced a divine revelation that spurred Abbot Hugh of Cluny (r. 1049–1109) to expand the abbey on an unprecedented scale.
Gunzo’s Vision: A Message from Saint Peter
The story of Gunzo’s vision is recorded in three key sources: an anonymous account of the Miracula of St. Hugh, Gilon’s Vita Hugonis (ca. 1120), and Hildebert of Le Mans’ Life of Hugh (1121). According to these texts, Gunzo, a former abbot who had retired to Cluny as a simple monk and psalmist (psalmista praecipuus), lay gravely ill in the monastery’s infirmary around 1080. Believing his death was imminent, he was visited in the night by the Apostles Peter and Paul, accompanied by Saint Stephen.
Gilon of Cluny describes the scene vividly:
A certain abbot of the monastery called Baume, by the name of Gunzo, a man of great simplicity and honesty, who had become a cloistered monk, lay wasting away in Cluny, suffering from paralysis… One night, he saw the Apostles Peter and Paul standing by him, accompanied by Saint Stephen, the first martyr.
Saint Peter then revealed to Gunzo that Cluny’s existing church was too small for the growing monastic community. He provided exact measurements for an expanded basilica and commanded Gunzo to relay this divine directive to Abbot Hugh. As further assurance, Peter promised Gunzo seven more years of life if he delivered the message. This structure, designed to house Cluny’s ever-expanding congregation and the thousands of pilgrims drawn to the monastery, would become the grandest expression of monastic architecture in medieval Europe.
The Misinterpretation of Gunzo’s Role
The account of Gunzo’s vision played a critical role in legitimizing the expansion project. However, later historians, most notably Kenneth Conant, misinterpreted the phrase architectum nostrum—used in the Miracula and Vita Hugonis—to mean that Gunzo himself was the architect of Cluny III. In reality, as the text makes clear, this designation referred to Abbot Hugh, who oversaw the project’s initiation and execution. The text states:
But the triumphant spirit of the still-flourishing Father [Hugh], remembering his former powers, decided to lay the foundations of a larger church in Cluny than had existed before, surpassing the usual laws of nature one by one.
Gunzo, though revered as the visionary catalyst for Cluny III, was not its architect. His role was that of a divine messenger, chosen to ensure that Hugh carried out the apostolic directive.
From Vision to Reality: The Construction of Cluny III
Construction on Cluny III commenced in 1088 under Abbot Hugh. The church was consecrated in successive stages, with Pope Urban II consecrating the high altar in 1095 during the Council of Clermont, at which he also called for the First Crusade. The final completion of the vast complex, including its famed five-aisled nave, two massive western towers, and a monumental transept, was achieved by 1130 under Peter the Venerable (r. 1122–1156).
Cluny III represented an architectural achievement without precedent. With an interior length of approximately 187 meters and a vault height of 30 meters, it eclipsed even contemporary cathedrals in scale. Its harmonious proportions, based on musical ratios, have been suggested to reflect the influence of medieval music theory. Conant proposed that Gunzo, as a trained psalmista (psalm singer), might have had knowledge of Vitruvian architectural principles, but there is no evidence to support this claim.
A Monastic Vision Realized
Gunzo’s vision of Saint Peter, recorded and propagated by Cluniac chroniclers, was not merely a pious anecdote but a crucial element in justifying Cluny III’s construction. By situating the church’s origins in divine will, the Cluniac order reinforced the necessity of its ambitious expansion. While later historians mistakenly credited Gunzo with architectural design, his true role was as a conduit for a prophetic revelation, one that ultimately led to the realization of the largest religious structure in Christendom until the Renaissance rebuilding of St. Peter’s Basilica in Rome.
In this way, Cluny III stands as a testament to medieval monastic ambition, where faith, architecture, and divine inspiration merged to create one of the most extraordinary ecclesiastical monuments of its time.
Dr Lorris Chevalier, who has a Ph.D. in medieval literature, is a historical advisor for movies, including The Last Duel and Napoleon. Click here to view his website.
Click here to read more from Lorris Chevalier
Top Image: The consecration of Cluny III – Bibliothèque nationale de France MS Latin 17716 fol. 91r
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