Out of these conditions grew the earliest of the universities. No definite dates for the beginnings of Paris, Bologna, Oxford, etc., can be assigned, but the twelfth and thirteenth centuries are to be considered their great formative period. Bologna was specifically the creation of the revived study of the Roman law and of the fame of the great law teacher Irnerius. The university sprang from a series of organizations effected first by the students and later by the masters, or teachers, and modeled after the guilds of workmen. It became the pattern for most of the later Italian and Spanish universities. Paris arose in a different way. It grew directly out of the great cathedral school of Notre Dame and, unlike Bologna, was an organization at the outset of masters rather than of students. It was presided over by the chancellor, who had had charge of education in the cathedral and who retained the exclusive privilege of granting licenses to teach (the _licentia docendi_), or, in other words, degrees.[495] Rising to prominence in the twelfth century, especially by virtue of the teaching of Abelard (1079-1142), Paris became in time the greatest university of the Middle Ages, exerting profound influence not only on learning, but also on the Church and even at times on political affairs. The universities of the rest of France, as well as the German universities and Oxford and Cambridge in England, were copied pretty closely after Paris. 60. Privileges Granted to Students and Masters Throughout the Middle Ages numerous special favors were showered upon the universities and their students by the Church. Patronage and protection from the secular authorities were less to be depended on, though the courts of kings were not infrequently the rendezvous of scholars, and the greater seats of learning after the eleventh century generally owed their prosperity, if not their origin, to the liberality of monarchs such as Frederick Barbarossa or Philip Augustus. The recognition of the universities by the temporal powers came as a rule earlier than that by the Church. The edict of the Emperor Frederick I., which comprises selection (a) below, was issued in 1158 and is not to be considered as limited in its application to the students of any particular university, though many writers have associated it solely with the University of Bologna. That the statute was decreed at the solicitation of the Bologna doctors of law admits of little doubt, but, as Rashdall observes, it was "a general privilege conferred on the student class throughout the Lombard kingdom."[496] By some writers it is said to have been the earliest formal grant of privileges for university students, but this cannot be true as Salerno (notable chiefly for medical studies) received such grants from Robert Guiscard and his son Roger before the close of the eleventh century.