In 1245, when twenty-four years of age, Bonaventure received his degree of Bachelor. Following {12} this came the necessary letters from the Minister-General, our Saint then fulfilling the office of Professor to his own brethren and at times teaching publicly in the University under the guidance of a fully-qualified lector. That same year Alexander died, and the chair thus vacated was filled by John of La Rochelle. Three years later, however, he resigned, and then at the command of the Minister-General, John of Parma, and at the earnest entreaty of the authorities of the University, Bonaventure succeeded to the post. This took place in 1248. Bonaventure was now a Licentiate, i.e. he was "licensed" or allowed to lecture publicly in view of his qualifications being recognized. It was no doubt a trial to his humility to follow so eminent a light as the "Monarch of Theologians," but fortunately personal distrust yielded to obedience. One of the ancient chroniclers, referring to this event, shows us Bonaventure as his contemporaries saw him. "This Brother Bonaventure," writes Blessed Francis of Fabriano, "was a most eloquent man, wonderful in his understanding of the Sacred Page and of the whole of Theology. He was also an excellent lecturer, a very fine preacher and in his presence every tongue was hushed." Bonaventure occupied this post from 1245 to 1257, and during that time acquired those stores of knowledge which he at first communicated to his pupils in the form of lectures, and then, with after-thoughts, corrections and additions bequeathed to {13} the world in the four folio volumes known as "The Commentary on the Sentences of the Lombard". His love of God growing in proportion, Bonaventure ultimately reached those sublime heights of contemplation which earned for him the title of Seraphic Doctor. To the Saint his youthful age seemed unequal to the fulfilment of such a task. His superiors, however, in laying on him the burden of obedience, felt assured that he would more than justify the wisdom of their appointment. And indeed so exceptional were the natural and supernatural gifts of this Seraphic Doctor that Sixtus IV. could say of him in his Bull of Canonization: "Such things he uttered on sacred science that the Holy Ghost would seem to have spoken through his mouth." And again, "Enlightened by Him Who is the Light, the Way, the Truth and the Life, in the space of a few years he attained to incredible knowledge".