In 1256, at the early age of thirty-five, he became general of his order, a post which he held till his death. He did much to ennoble and purify the order, and to bring it back to orthodoxy, from which then, as nearly always, it was strongly inclined to swerve. In 1265 Clement V. nominated him to the see of York; but Bonaventura, unwilling probably to face so rude a climate and people, persuaded the Pope to withdraw the nomination. A few years later, under Gregory X., he was raised to the cardinalate and appointed bishop of Albano. In 1274 he attended the Council of Lyons, and must have been deeply affected when he learned that Thomas Aquinas had died on his way thither. The success of the efforts of the council to come to terms with the Greeks was mainly due to him. This was Bonaventura's last work on earth. He died before the council was over, and was honored with a funeral whose solemnity and magnificence have seldom been equaled. It was attended by the Pope, the Eastern Emperor, the King of Aragon, the patriarchs of Antioch and Constantinople, and a large number of bishops and priests. His relics were preserved with much reverence by the Lyonnese until the sixteenth century, when the Huguenots threw them into the Saône. In 1482 he was canonized by Sixtus IV., and in 1588 declared a doctor of the Church by Sixtus V. Dante places him in the Heaven of the Sun. Bonaventura is the sweetest and tenderest of all the mediæval saints. His mode of teaching was so inspiring that even in his lifetime he was known as the "Seraphic Doctor." He was a voluminous writer, his works in the Lyons edition of 1688 filling seven folio volumes. They consist largely of sermons, and commentaries on the Scriptures and the 'Sentences' of Peter the Lombard. Besides these, there is a number of 'Opuscula,' mostly of a mystic or disciplinary tendency. Most famous among these are the 'Breviloquium,' perhaps the best compend of mediæval Christian theology in existence; and the 'Itinerarium Mentis in Deum,' a complete manual of mysticism, such as was aspired to by the noblest of the mystics; a work worthy to be placed beside the 'Imitation of Christ,' though of a different sort.