In 1648, the year in which the Thirty Years’ War came to an end, the magistrates of Frankfort gave up formally the attempts to supervise the book-production of the city. In 1662, the magistrates found occasion for protests against the imperial regulations for the control of the book-trade. The emperor, in his edict of March 18, 1662, was acting under the counsel of his Jesuit advisers. The magistrates were speaking as the representatives of the publishers, and, as they contended, for the interests of the community as a whole. In 1665, under some counsel which proved to be very ill-advised, the imperial commissioners undertook to fix the prices of the books presented for sale at the Frankfort Fair. It was contended that the commissioners who had been charged with the work of censorship had no authority to take upon themselves the determination of a business detail. It was very certain that they did not have the expert knowledge required for the task, but it was, of course, the case that no commissioners could have carried out successfully any such system. This price regulation proved to be one of the most effective of the various factors which caused the replacing of Frankfort by Leipsic as the centre of the publishing and bookselling interests of Germany. [Sidenote: Strasburg] In 1488, the city of Strasburg established under the directions of the emperor a local censorship supervised by the magistracy. The first book prohibited under this regulation was the _Germania Nova_ of Murner, issued in 1502. In 1501, Alexander VI publishes a bull prohibiting the printing, within the territories in question, of any books that have not secured an approval, in the form of a privilege, from the Archbishops of Cologne, Mayence, Treves, and Magdeburg, or from their vicars-general.[144] [Sidenote: Leipsic]