21 But, furthermore, Our predecessors in the Roman pontificate have celebrated the wisdom of Thomas Aquinas by exceptional tributes of praise and the most ample testimonials. Clement VI in the bull In Ordine; Nicholas V in his brief to the friars of the Order of Preachers, 1451; Benedict XIII in the bull Pretiosus, and others bear witness that the universal Church borrows lustre from his admirable teaching; while St. Pius V declares in the bull Mirabilis that heresies, confounded and convicted by the same teaching, were dissipated, and the whole world daily freed from fatal errors; others, such as Clement XII in the bull Verbo Dei , affirm that most fruitful blessings have spread abroad from his writings over the whole Church, and that he is worthy of the honor which is bestowed on the greatest Doctors of the Church, on Gregory and Ambrose, Augustine and Jerome; while others have not hesitated to propose St. Thomas for the exemplar and master of the universities and great centers of learning whom they may follow with unfaltering feet. On which point the words of Blessed Urban V to the University of Toulouse are worthy of recall: "It is our will, which We hereby enjoin upon you, that ye follow the teaching of Blessed Thomas as the true and Catholic doctrine and that ye labor with all your force to profit by the same."(35) Innocent XII, followed the example of Urban in the case of the University of Louvain, in the letter in the form of a brief addressed to that university on February 6, 1694, and Benedict XIV in the letter in the form of a brief addressed on August 26, 1752, to the Dionysian College in Granada; while to these judgments of great Pontiffs on Thomas Aquinas comes the crowning testimony of Innocent VI: "His teaching above that of others, the canonical writings alone excepted, enjoys such a precision of language, an order of matters, a truth of conclusions, that those who hold to it are never found swerving from the path of truth, and he who dare assail it will always be suspected of error."(36)
Source: Aeterni Patris (Vatican.va)