Abelard began it. After his first visit to Paris in 1100, he seems to have passed several years elsewhere, while Guillaume de Champeaux in 1108, retired from the school in the cloister of Notre Dame, and, taking orders, established a class in a chapel near by, afterwards famous as the Abbaye-de-Saint-Victor. The Jardin des Plantes and the Gare d'Orleans now cover the ground where the Abbey stood, on the banks of the Seine outside the Latin Quarter, and not a trace is left of its site; but there William continued his course in dialectics, until suddenly Abelard reappeared among his scholars, and resumed his old attacks. This time Abelard could hardly call himself a student. He was thirty years old, and long since had been himself a teacher; he had attended William's course on dialectics nearly ten years before, and was past master in the art; he had nothing to learn from William in theology, for neither William nor he was yet a theologist by profession. If Abelard went back to school, it was certainly not to learn; but indeed, he himself made little or no pretence of it, and told with childlike candour not only why he went, but also how brilliantly he succeeded in his object:-- I returned to study rhetoric in his school. Among other controversial battles, I succeeded, by the most irrefutable argument, in making him change, or rather ruin his doctrine of universals. His doctrine consisted in affirming the perfect identity of the essence in every individual of the same species, so that according to him there was no difference in the essence but only in the infinite variety of accidents. He then came to amend his doctrine so as to affirm, not the identity any longer, but the absence of distinction--the want of difference--in the essence. And as this question of universals had always been one of the most important questions of dialectics--so important that Porphyry, touching on it in his Preliminaries, did not dare to take the responsibility of cutting the knot, but said, "It is a very grave point,"--Champeaux, who was obliged to modify his idea and then renounce it, saw his course fall into such discredit that they hardly let him make his dialectical lectures, as though dialectics consisted entirely in the question of universals.