Thomas of York was a gifted theologian of the second generation at the Oxford Greyfriars. He seems to have entered the order in his native York at the city's Greyfriars adjacent to the river Ouse in the 1230s and then advanced to the custodial school, where he had a thorough grounding in the liberal arts. He may have reached Oxford by 1245, when he was asked to dispatch some manuscripts to Adam Marsh, who had accompanied Robert Grosseteste, bishop of Lincoln, to Lyon in preparation for the ecumenical council of that year. He was described as the ‘most obedient servant’ of Bishop Grosseteste and advised William of Nottingham, the minister provincial, on matters pertaining to the English province of the Franciscan order. During this period he sat at the feet of Adam Marsh and Eustace of Normanville, the first and third regent masters of Oxford. In 1251 there was speculation that he might be assigned as the lector to another friary. Adam, however, intervened to dissuade William of Nottingham, urging that Thomas should remain at Oxford to prepare himself for the office of regent master. When Thomas was nominated as the fourth regent master in late 1252, the University of Oxford pointed out that he had not ruled in the faculty of arts, whereas the three previous incumbents – Adam Marsh, Ralph of Corbridge and Eustace of Normanville – had joined the order as Masters of Arts. Despite this omission, the quality of Thomas's studies was recognised. Indeed, the university had no qualms about his level of preparation ‘on account of his distinguished conduct, his intellectual gifts, and his proven learning, which commend him to many and great persons’. The university issued a grace to permit Thomas to become the next regent master. Little is known about his teaching there. It is unclear whether he commented on the Sentences of Master Peter Lombard, as Richard Rufus of Cornwall had done in 1250. After one or two years at Oxford, he was appointed to lecture at Cambridge as the sixth regent master. He was credited with some scriptural commentaries and was the first English friar to be drawn into the polemics at Paris between the friars and the secular masters in the middle of the 1250s. His Manus que contra omnipotentem combats the teaching of Master William of Saint-Amor. His Sapientiale may have been begun at Oxbridge. One of the scholars who made extensive use of Thomas's work was Berthold of Moosburg, the principal Dominican lector at Cologne in the early fourteenth century.

The foreword to this edition of the Sapientiale was written by Fiorella Retucci and the introduction was jointly compiled by Retucci and Antonio Punzi. The Sapientiale has gradually been brought to the attention of the scholarly community during the twentieth century. Martin Grabmann expressed his interest in this treatise as early as 1913. Fr Ephrem Longpré ofm published a penetrating study (Fr. Thomas d'York, O.F.M.: la première somme métaphysique du XIII siècle) of the Sapientiale in 1926. Etienne Gilson lamented the absence of a critical edition of Thomas's text. Reginald O'Donnell of the Pontifical Institute of Mediaeval Studies planned to compile a critical edition. The key manuscripts are described by Retucci and Punzi: first, Biblioteca Nazionale Centrale, Firenze, Conv. Soppr.A.VI.437, an English manuscript from the second half of the thirteenth century; secondly, Biblioteca Apostolica Vaticana, Città del Vaticano, ms Vat. lat. 6771; thirdly, another thirteenth-century manuscript, perhaps from Italy, Biblioteca Apostolica Vaticana, Città del Vaticano, ms Vat. lat. 4301. mss F and V have incipits from the Sapientiale, while ms V has one from the Comparatio sensibilium. The editorial complexities of the Sapientiale are described by Punzi, who draws attention to marginalia in the manuscripts. This is the first volume of four to be published.

Philosophers are frequently quoted in this metaphysical text, with Plato, Aristotle, Averroes, Albumasar, Algazel and Cicero and Seneca, Boethius and the anonymous Liber de causis. There are numerous quotations from Moses Maimonedes's Dux neutrorum. Thomas made use of the writings of Dionysius the Areopagite, Augustine of Hippo, John of Damascus, Anselm of Canterbury, Bernard of Clairvaux and Alan of Lille. This text lifts the veil on the early Franciscan school at Oxford and confirms the pervasive influence of Augustine and the increasingly audible voice of Anselm's Cur Deus homo. Thomas uses Bishop Grosseteste's translations of Aristotle's Nicomachean ethics and John of Damascus’ De fide orthodoxa, although in each case he prefers the earlier translations by Eustratius and Burgundio of Pisa respectively. He shows an awareness of Thomas Gallus’ recently published commentaries on Dionysius the Areopagite. One typographical slip in the index indicates that Grosseteste's translation of the Nicomachean ethics was to be found on page 70 rather than page 71. The Sapientiale represents the first attempt at metaphysical systematisation. This attractive volume will be welcomed by historians of the Oxford school in general and by students of the Franciscan school in particular. The scholarly community eagerly awaits the publication of the next three parts of this treatise.