In May 1961, the first edition of the Muzički biennale, Internacionalni festival suvremene muzike was held in the Croatian capital Zagreb, which then was the second largest city of Yugoslavia. The festival guests included Witold Lutosławski, who delivered a lecture on Polish contemporary music, illustrating it with recordings of works by his younger colleagues. Considering the history of the demolition of the ‘edifice of Classical musical language’, he declared his faith that ‘the more quickly the old musical material is dismantled, the more quickly new material will arise. And from it, through synthesis, it will be possible to forge new lasting conventions for a new Classical period’.
The festival audience could hear how he himself imagined the ‘forging of new conventions’ during the next edition of the Biennale, when Trois poèmes d’Henri Michaux was performed. That work required two conductors. Music history had previously known examples of three or even four conductors appearing in the concert hall at the same time (Stockhausen’s Gruppen and Carré), but they had all followed a shared, precisely notated score. In the Lutosławski, the situation was different: each of the conductors was working independently of the other; the music was notated in an aleatory fashion, and in two separate scores it gave independence to the chorus and the orchestra. Thus on the left of the platform the 23-strong Zagreb radio orchestra was conducted by the composer, whilst on the right the 20-strong chorus was led by the Croatian conductor Slavko Zlatić.
During that concert, on Friday 9 May 1963, Lutosławski made his public debut as a conductor. He had already stood before music ensembles many times before, including symphony orchestras, but always in a radio studio.