In his book, A History of Philosophy (Volume II): Augustine to Scotus, Copleston points out that a more authentic version of Aristotelianism was being propagated by Christian scholars like Boethius. He says that by coming up with several Latin translations of Aristotle’s works, the Christian scholars popularized Aristotelian logic and metaphysics in medieval Europe. He holds the Arab philosophers (mainly Averroes) responsible for fueling opposition to Aristotelianism.
Here’s an excerpt from Chapter 6, “Islamic and Jewish Philosophy Translations,” of Copleston’s A History of Philosophy (Volume II): Augustine to Scotus:
The Arabian philosophy was one of the principal channels whereby the complete Aristotle was introduced to the West; but the great philosophers of medieval Islam, men like Avicenna and Averroes, were more than mere transmitters or even commentators; they changed and developed the philosophy of Aristotle, more or less according to the spirit of neo-Platonism, and several of them interpreted Aristotle on important points in a sense which, whether exegetically correct or not, was incompatible with the Christian theology and faith. Aristotle, therefore, when he appeared to medieval Christian thinkers in the shape given him by Averroes, for example, naturally appeared as an enemy of Christian wisdom, Christian philosophy in the wide sense. This fact explains to a large extent the opposition offered to Aristotelianism in the thirteenth century by many upholders of the Christian tradition who looked on the pagan philosopher as the foe of Augustine, Anselm and the great philosophers of Christianity. The opposition varied in degree, from a rather crude dislike and fear of novelty, to the reasoned opposition of the thinker like St. Bonaventure; but it become easier to understand the opposition if one remembers that a Moslem philosopher such as Averroes claimed to give the right interpretation of Aristotle and that this interpretation was, on important questions, at variance with Christian belief. It explains too the attention paid to the Islamic philosophers by those (particularly, of course, St. Thomas Aquinas) who saw in the Aristotelian system not only a valuable instrument for the dialectical expression of Christian theology but also the true philosophy, for such thinkers had to show that Aristotelianism did not necessarily involve the interpretation given to it by the Moslems; they had to dissociate themselves from Averroes and to distinguish their Aristotelianism from his.