In his Decretum Gratian not only utilized previous canonical collections but also applied hermeneutic principles in the task of reconciling the contradictions which appeared to exist in the masses of received auctoritates. The achievement of a concordia between the discordantes canones was a fundamental purpose of the Decretum; if previous canonical collectors had used rules of reconciliation to remedy the difficulties in the sources which they used, Gratian made such rules the central principle of his whole edifice. Like Gratian Abelard in his Sic et Non made the task of reconciliation the cornerstone of his work and, as S. Kuttner observed, it is a stupendous fact of medieval history that within a decade or two such a synchronism and parallelism should occur in this respect and generally too between the birth of scholastic theology in northern France and the rebirth of jurisprudence in Bologna. F. Thaner in the year 1900 went so far as to state that Gratian, particularly in the first part of the Decretum, was directly influenced by the Sic et Non of Abelard. But Thaner's thesis has usually been judged to be too absolute since Abelard was, like Gratian, himself much influenced by earlier reconcilers such as Bernold of Constance, Ivo of Chartres and Alger of Lieége.