The difficulty of enforcing such a definition throughout almost the whole of Europe might seem likely to be great, but in point of fact it was inconsiderable. In the first half of the thirteenth century, the term Studium Generale was assuming recognised significance; a school which aspired to the name must not be restricted to natives of a particular town or country, it must have a number of masters, and it must teach not only the Seven Liberal Arts (of which we shall have to speak later), but also one or more of the higher studies of Theology, Law and Medicine (_cf._ Rashdall, vol. i. p. 9). But the title might still be adopted at will by ambitious schools, and the intervention of the great potentates of Europe was required to provide a mechanism for the differentiation of General from Particular Studia. Already, in the twelfth century, an Emperor and a Pope had given special privileges to students at Bologna and other Lombard towns, and a King of France had conferred privileges upon the scholars of Paris. In 1224 the Studium Generale of Naples was founded by the Emperor Frederick II., and in 1231 he gave a great privilege to the School of Medicine at Salerno, a Studium which was much more ancient than Bologna, but which existed solely for the study of Medicine and exerted no influence upon the (p. 009) growth of the European universities. Pope Gregory IX. founded the Studium at Toulouse some fifteen years before Innocent IV. established the Studium of the Roman Court. In 1254 Alfonso the Wise of Castile founded the Studium Generale of Salamanca. Thus it became usual for a school which claimed the status of a Studium Generale to possess the authority of Pope or Emperor or King.