fame of the master, who now stood forth a victorious champion of German national art, as opposed to the theories and methods of the French. These various professional journeys and the visit between the years 1715 and 1717 of Georg Erdmann, the friend of his youth, who, after completing his study of the law, had entered the Russian service in 1715, are the most important external events of Bach's stay in Weimar. If we glance at his creative activity during that period, we see that the principal emphasis falls upon his work as organ virtuoso and composer. Duke Wilhelm took great pleasure in his playing, and this incited him to use his utmost efforts in the art of handling his instrument. It was in Weimar that he wrote the larger number of his very numerous organ compositions, and he also made much progress here in the art of vocal composition, besides becoming thoroughly acquainted for the first time with Italian chamber music. The duke's nephew, Prince Johann Ernst, was of a decidedly musical turn, and, with the aid of Walther, had even made attempts at composition. In gratification of his tastes, frequent concerts of chamber music were given at the castle, Bach acting as leader. The violin concerto, which had just been revived in Italy through the efforts of Torelli and Vivaldi, and the violin sonata in the form established by Corelli, were favorite varieties of this sort of music, in which Bach soon developed a strong interest, as is shown by the fact that he arranged for the clavier and the organ about twenty of Vivaldi's concertos. These works are not arrangements in the ordinary sense, but are rather expansions of the original motives. By means of an animated bass, a richly melodious baritone and artistic contrapuntal imitations, Bach converted his material into something at once novel and charming. He also took themes from the violin sonatas of Corelli and Albinoni, while he richly elaborated and fashioned into an organ fugue, the leading motive of a composition by the Venetian Legrenzi. That he entered very heartily into the spirit of the Italian music of the day is evident from his causing a copy to be made for himself of an important production of Frescobaldi, the greatest Italian organ master. This work, entitled "_Fiori Musicali_" appeared in 1635. [Illustration: JOHANN SEBASTIAN BACH. From an oil portrait owned by the Bach family until 1828. Now in possession of A. Grenser, of Vienna.]