TOMMASO GALLO (of Vercelli). — Also called T. of Saint-Victor or T. of Vercelli, he was already a Canon Regular of the Abbey of Saint-Victor in Paris in 1218, when he composed his commentary on Isaiah.
From that time onward he had become familiar with the works of the Pseudo-Dionysius. In the retinue of Cardinal Guala Bicchieri he came to Italy (1219) and at Vercelli founded the monastery of Saint Andrew, of which in 1224 he was prior and in 1226 abbot. To the early years of his stay at Vercelli belong the commentary on the Song of Songs and the Glossae in cantica; in 1227 the second commentary on the Song of Songs; in 1238 the Extractio from various works of the Pseudo-Dionysius; in 1241 the Explanatio in mysticam theologiam, followed by the Explanatio de divinis nominibus. In 1238 he hosted Emperor Frederick II, and in 1243, when Vercelli declared itself Guelph, the abbot fled with the Ghibellines to Ivrea. In the same year he published at Vercelli the Explanatio de caelesti hierarchia. Deposed for his support of the Ghibellines, he refused to submit and settled again at Ivrea, where he devoted himself to a third commentary on the Song of Songs, the Explanatio in ecclesiasticam hierarchiam, and other mystical works. He died, perhaps having returned to his abbey, in December 1246. He deepened the study of the writings of the Pseudo-Dionysius and strove to reconcile them with Holy Scripture and with the spirit of the theology of John the Saracen. Great was the influence of his writings on Franciscan and Cistercian mysticism, as well as on German mysticism from Meister Eckhart to Cardinal Cusanus.