Scotism is the philosophical school and theological system named after John Duns Scotus, a 13th-century Scottish philosopher-theologian. The word comes from the name of its originator, whose Opus Oxoniense was one of the most important documents in medieval philosophy and Roman Catholic theology, defining what would later be declared the dogma of the Immaculate Conception by Pope Pius IX in his constitution Ineffabilis Deus on 8 December 1854. Development Scotism developed out of the Old Franciscan School, which dominated theology during the Middle Ages. This school of thought initially followed Augustinism, which dominated theology at the time. Scotus found the ground already cleared for the conflict with the followers of Aquinas. He made very free use of Aristotelianism, but in its employment exercised sharp criticism, and in important points adhered to the teaching of the Older Franciscan School–especially with regard to the plurality of forms or of souls, the spiritual matter of the angels and of souls, etc., wherein he energetically combatted Aquinas. Scotism, or what is known as the Later Franciscan School, is thus only a continuation or further development of the older school, with a much wider, although not exclusive acceptance of Peripatetic ideas. The difference between Thomism and Scotism could be expressed by saying that, while both derive from Arabic Neoplatonized Aristotelianism, Thomism is closer to the orthodox Aristotelianism of Maimonides, Averroes and Avicenna, while Scotism reflects the Platonizing tendency going back through Avicebron, the Brethren of Purity, the Liber de Causis and Proclus to Plotinus. Concerning the relation of these schools to each other, or the relation of Scotus to Alexander of Hales and St. Bonaventure, consult the work of the Flemish Recollect, Mathias Hauzeur. It is notable that, while Thomism became the official philosophy of the Church, Scotist influence prevailed on a number of important points, not least the doctrine of the Immaculate Conception. Doctrinal conflicts within the Catholic Church Nominalism is older than Scotus, but its revival in Occamism may be traced to the one-sided exaggeration of some propositions of Scotus. Scotist Formalism is the direct opposite of Nominalism, and the Scotists were at one with the Thomists in combatting the latter; Occam himself was a bitter opponent of Scotus. The Council of Trent defined as dogma a series of doctrines especially emphasized by the Scotists (e.g. freedom of the will, free co-operation with grace, etc..). In other points the canons were intentionally so