 But the work on logic which was both technically advanced (and therefore unlike Ghazâlî's) and influential on later Arabic logicians (and therefore unlike Averroes') was done by Avicennan logicians who had begun to repair and reformulate Avicenna's work. Just as Avicenna had declared himself free to rework Aristotle as Intuition dictated, so too these logicians working on Avicenna's logic regarded themselves as free to repair the Avicennan system as need arose, whether from internal inconsistencies, or from intellectual requirements extrinsic to the system. A major early representative of this trend is ‘Umar ibn Sahlân as-Sâwî (d. 1148) who began, in his Logical Insights for Nasîraddîn, to rework Avicenna's modal syllogistic.[13] It was to be his students and their students, however, who would go on to make the final changes to Avicennan logic that characterized the subject that came to be taught in the madrasa.