By Pope Sixtus V
Truly already among these [saints], whom the great Lord willed to fill with a spirit of intelligence, and whom each one has sent forth the utterance of his wisdom like a shower upon the Church of God, is St Bonaventure numbered, as a Confessor, a Pontiff, and an exceptional Doctor in the same Catholic Church, he whom Our predecessor, Pope Sixtus IV, of happy remembrance, on account of the admirable sanctity of his life and very excellent doctrine inscribed among the number of the saints.
For having been born at Bagnoregio in Tuscany, so that he might satisfy the pious vow of his mother, he entered as an adolescent into the Religion of St Francis, by means of whose still recent footsteps the new soldier of Christ progressing humbly and constantly, drank the most healthful observance of regular norms with such ardour of spirit and avidity of heart, that there appeared in him the highest sanctity, and with innocence and chastity of life, holy humility, patience, meekness, disdain of earthly things, desire for those heavenly, he was an example to and the admiration of all. Inflamed in such great sweetness and fervour of divine love, his spirit was so rapt in God, that already as one introduced into the wine cellar of the Spouse and drunk with the best wine of charity, he seemed to gaze everywhere upon Jesus Christ Crucified and Suffering, and to dwell in His wounds. Truly to this exceptional holiness of life did this man of God join the great praise of outstanding doctrine, with God so disposing, so that for His glory and the utility of the Church, he would not only make very great progress in example, but in word and erudition. And so when in the study of the Sacred Letters, the reading of the holy Fathers and in the very necessary discipline of scholastic theology, having been employed most diligently by Alexander of Hales, the distinguished theologian of that era, for a brief space of time, with the goodness of surpassing genius, by assiduous labour, and what is chief of all, with the grace of the Holy Spirit, who moulded him on all sides as a golden vessel for a chosen honour, he made such progress and arrived at such perfection of doctrine, that decorated in solemn custom with the distinctions of a Master in Theology in the frequented lecture hall of Paris, he taught sacred theology publicly in the same place.
Truly did he attain such great praise in the gift of interpreting and in the science of all theology, that the most learned men admired his doctrine and erudition. And indeed there are extant many, moving and very bright writings of this holy man, which still are of great utility to the Church and are not mediocre, by the benifice of God, everyone of which both erudite men, of Our age and ages past, have read with much fruit and very entirely approved, so great was he in theology, that they declare him sufficient.
For he left those monuments of his divine genius to those who would come after him, by which questions, very difficult and involuted with many obscurities, are explained methodically and in order, straightforwardly and lucidly, with a great bounty of the best arguments, the truth of the Catholic Faith is illustrated, pernicious errors and profane heresies are overthrown, and the pious minds of the faithful are admirably inflamed to the love of God and the desire of the celestial fatherland.
For there was in St Bonaventure something pre-eminent and unique, so that he stood out not only in subtlety of arguing, in facility of teaching, in cleverness of defining, but he excelled in a certain divine strength of thoroughly stirring up souls.