During the period Busoni undertook teaching at masterclasses at Weimar, Vienna and Basel. In 1900 he was invited by Duke Karl-Alexander of Weimar to lead a masterclass for fifteen young virtuosi. This concept was more amenable to Busoni than teaching formally in a Conservatory: the twice-weekly seminars were successful and were repeated in the following year. Pupils included Maud Allan, who later became famous as a dancer and remained a friend. His experience in Vienna in 1907 was less satisfactory, although amongst his more rewarding pupils were Ignaz Friedman, Leo Sirota, Louis Gruenberg, Józef Turczyński and Louis Closson; the latter four were dedicatees of pieces in Busoni's 1909 piano album "An die Jugend". But arguments with the Directorate of the Vienna Conservatoire, under whose auspices the classes were held, soured the atmosphere. In the autumn of 1910 Busoni gave masterclasses and also carried out a series of recitals in Basel.