GUGLIELMO di SAINT-THIERRY. — Cistercian theologian, born at Liège around 1085, died at Signy on 8 September 1148. Of distinguished family, he probably studied at the school of Anselmo di Laon. Having entered the Benedictine abbey of St-Nicaise (Reims), he subsequently became a monk there, and in 1119 was elected abbot of St-Thierry, near Reims, where he governed wisely. Won over by the affectionate friendship of s. Bernardo, although dissuaded by him, he resigned as abbot and in 1135 joined the Cistercians of Signy (diocese of Reims), where he spent his final years in fervent contemplation, though always alert to the dangers that, in that period of intellectual ferment, could threaten the faith. It was precisely in 1138 that, through a moving letter (PL 182, 531-39), he prompted s. Bernardo’s timely Abelardo (v.), later condemned at the Council of Sens (1140) and by Rome. With equal zeal he opposed the doctrinal deviations of Guglielmo di Conches in the De erroribus Guillelmi de Conchis (ibid. 180, 333-40) and of Gilberto Porretano (v.). In the Cistercian Order he bears the title of blessed.
Before withdrawing to Signy he had written various works: the De contemplando Deo (ibid. 185, 365-80), attributed to s. Bernardo; the De natura et dignitate amoris (ibid. 185, 379-408); the De Sacramento altarii (ibid. 180, 345-66), which deals with transubstantiation, the multipresence of Christ’s body, the accidents, and the duplex manducatio, with the aim of reconciling the apparent antinomies in the patristic texts concerning the Eucharistic mystery. In the Migne edition (ibid. 341-44), this work is preceded by G.’s Eucharistic letter to Ruperto di Deutz; the Excerpta ex libris s. Gregorii papae super cantica canticorum (ibid. 411-74) and the Commentarius in Cantica Canticorum ex scriptis s. Ambrosii (ibid. 15, 1947 ff.): two skillfully compiled florilegia; De natura corporis et animae libri duo (ibid. 180, 695-726): in the first book he offers an almost anatomical analysis of the human body following the model of Costantino l'Africano and the Arab physicians, while in the second he presents an anthropology taken three-quarters from the De hominis opificio of s. Gregorio Nisseno, in the Latin translation of Scoto Eriugena; Meditativae orationes (ibid. 205-47): a personal work, a faithful mirror of his fervent soul. These later writings were certainly completed at Signy, where circumstances imposed a new rhythm upon his pen: Expositio altera super Cantica Canticorum (ibid. 473-546): it extends to chapter 3, V. 3; the idea of love’s influence upon the knowledge of God governs the entire work, which draws its inspiration from Origene, whose partial translation by Rufino G. had before his eyes, and from the celebrated commentary of s. Bernardo; Expositio in epist. ad Romanos (ibid. 547-694): an extensive commentary drawn largely from s. Agostino; Disputatio adversus Abaelardum (ibid. 249-82): it refutes Abelardo’s errors concerning the principal Christian dogmas; its doctrine of Redemption is particularly important. After the condemnation of the audacious philosopher, his former fellow student, G. attempted to develop theology in the desire to provide better guidance for minds led astray by error; thus arose the Sententiae de fide
(lost), a kind of treatise De Deo Uno et Trino inspired by the doctrine of s. Agostino and Boezio; the Speculum fidei (ibid. 365-98): an original psychology of faith, in which the motif amor ipse intellectus est is dominant; the Aenigma fidei (ibid. 397-440): a subtle synthesis, suffused with piety, concerning the transcendence of the Trinitarian mystery, in opposition to the attempts of Abelardo and Guglielmo di Conches to rationalize its content. Shortly before his death he composed the Epistola ad fratres de Monte Dei, called the Epistola aurea (ibid. 184, 307-54), at the request of the Carthusians of Mont-Dieu, near whom he had spent delightful days for his spirit: it is a true treatise de vita solitaria, based on the Origenian trichotomy of the psychics (beginners), gnostics (those making progress), and pneumatics (the perfect). Soon attributed to s. Bernardo, it enjoyed the popularity of the works of the holy Doctor; used by s. Antonio da Padova, Davide di Augusta, Ruysbroeck, and Taulero, it was restored to its true author only in 1662 by Tissier, immediately followed by Mabillon. The Vita Bernardi (ibid. 185, 225-66), composed with an alert critical sense, extends to 1130; death prevented G. from completing this sincere tribute to his great friend. Other writings were attributed to him, particularly the Disputatio catholicorum patrum adversus dogmata Petri Abaelardi, but it is the work «cuiusdam abbatis nigrorum monachorum» (Goffredo d'Auxerre, ibid. 185, 596).
A man of tradition, G. lived in constant communion of ideals with the Fathers, creating around himself a «paradisus claustralis», a warm and luminous climate in which the origin and development of his spiritual doctrine are enveloped. Although subjugated by the strong personality of s. Bernardo, he preserved his doctrinal autonomy, which is reflected in unmistakable attitudes and turns of expression. This Cistercian, who lacked neither genius nor artistry, whose religious lyricism was sustained by a singular purity of life, after eight centuries of undeserved oblivion now sees that atmosphere of admiration restored around his person and work which his contemporaries lavished upon him, and his candid figure advances beside that of his great friend, the Mellifluous Doctor.