In 1507, when only thirty, he was made Prior, and thus became responsible for much of the management of the abbey. In spite of this he kept up his studies; but only at the cost of great physical efforts, robbing himself of sleep and working through long hours of the night. To this period, 1507-9, belongs his most considerable undertaking, an _Auctarium de scriptoribus ecclesiasticis_, which had its origin in his admiration for Trithemius. In his Johannisberg days, as we have seen, he had met the great historian-abbot, though in a humble capacity. His own Abbot shared with Trithemius the duty of making the triennial visitations of the Benedictine houses in that district; and Butzbach, as the Abbot's servant, often rode with them. Trithemius noticed the young lay-brother who seemed so interested in study, and occasionally gave him a word of encouragement. Indeed it was the story of Trithemius' life--repeated with wonder by many lips--which had spurred Butzbach on to go to Deventer: how as a boy he had worked with his stepfather in the mill at Trittenheim, and at twenty-one was still labouring with his hands. One day he was carting material for a new pilgrimage-church on the hill, when the call came to him. He returned home, put up his horse and wagon, and without a word to any one walked off to Niederwesel to begin learning grammar amongst the little boys; and yet in a short time he had risen to be Abbot, and had won a wide reputation. At Laach Butzbach for the first time set eyes on Trithemius' works. One of these was a _Liber de scriptoribus ecclesiasticis_, printed by John Amorbach at Basle in 1494--a sort of theological _Who's Who_, giving the names of authors ancient and modern with lists of their writings. Butzbach continued it with an _Auctarium_, into which he hooked almost every writer he could find, whether ecclesiastical or not. It is a large book, still remaining in manuscript at Bonn, as it was written out for him by two very inefficient novices. The date of its composition is abundantly indicated by the notes with which he terminates his notices of living authors: 'Viuit adhuc anno quo hec scribimus 158' or 159.[13] Such a compilation, in so far as it deals with contemporary writers, might have had considerable value; but unfortunately, like some of Trithemius' work, it is an uncritical performance and contains ridiculous blunders, which impair the credit of its statements when they cannot be checked. Industry and devotion to learning are not the sole qualifications for a scholar. [13] = 1509. By a reverse process Bruno Amorbach writes 10507 for 1507.