 In the mid-thirteenth century, university philosophers were enthused by the newly available Aristotelian material, complimented by Avicenna’s presentations and understood with the aid of Averroes’s  commentaries.[19]  The two most famous Parisian Arts masters, Siger of Brabant and  Boethius of Dacia,  working in the 1260 and 1270s, tried to develop Aristotelianism within its own terms, not merely independently of revealed doctrine (as they were required to do in the Faculty of Arts), but also irrespective of whether it contradicted Christian teaching. The Dominican theologian  Thomas Aquinas  (1225–74) was no less enthusiastic an Aristotelian, but he had an almost unlimited confidence that Aristotle had reached demonstrative conclusions which must, therefore, be true and, equally, because true, not be in contradiction with Christian doctrine (though Christian doctrine also included elements that could not be known except through revelation)  (§3.1,  §3.3). Siger and Boethius of Dacia were among the targets of a condemnation directed by the Bishop of Paris in 1277 (see entry on the  Condemnation of 1277)  against thinkers in the university. Aquinas, recently dead, did not escape completely, and he remained a controversial figure, though an authority for Dominicans (see also  Aquinas’s moral, political, and legal philosophy).