And so shaking the dust of Geneva from his feet he journeyed to Lyons, where he failed utterly to find occupation, and then on to Toulouse, where he remained about two years. Here he took a Doctorate in Theology in order to compete for a vacant chair. To this he was elected by the students, as the custom then was in most of the _scholia_ or universities. For two sessions he lectured on Aristotle. Had this University required of him that he should attend mass, as did some others, he could not have done so, owing to his excommunication; though just why exclusion from a Calvinistic academy should debar him from Catholic mass does not appear. Toulouse was a _warm_ place for heretics; the burning of 14,000 of them at its capture will prove this. A few years (35) after he left it Vanini was burned for heretic notions. It is hardly to be believed that Bruno could pass two years or more here without controversies arising from his teaching. But his nominal reason for leaving, in 1581, and going to Paris, was the war then raging in Southern France, under Henry of Navarre. Before leaving Toulouse he completed his "_Clavis Magna_" or "Great Key," the last word--as he seemed to think--on the art of memory. Only one volume of this great work, which, in his peculiarly egotistical way, he said is "superlatively pregnant," was ever published, and that in England, the "_Sigillus Sigillorum_." It must not be forgotten that it was on both teaching and practising this art of memory that Bruno, throughout his career, prided himself. He was even not averse, at least at certain periods of his career, to the belief that he had some secret system for this purpose, or even received occult aid. But when summoned before Henry III, to whose ears had come his fame, and asked whether the memory he had and the art he professed were natural or due to magic, he proved that a good memory was a cultivated natural product. He then dedicated to the King a book on "_The Art of Memory_." But this was shortly after his arrival in Paris, in 1581, where he quickly became famous. A course of thirty lectures on "_The Thirty Divine Attributes_" of St. Thomas Aquinas would have given him a chair, could he have attended mass.