Mycielski met Jarosław Iwaszkiewicz before the war, in the circle of people gathered around Karol Szymanowski. In 1945, shortly after returning to Poland, he visited Iwaszkiewicz in Stawisko. This was the beginning of their friendship, which lasted until Iwaszkiewicz’s death. The two men were close as individuals remembering the pre-war world perfectly and trying to find a place for themselves in communist Poland. Mycielski also highly valued the oeuvre of his friend. He used Iwaszkiewicz's poems to compose the song Brzezina for soprano and piano as well as the cycle Krągły rok [All Year Round] for baritone and piano. Together they created the ballet Zabawa w Lipinach [Merrymaking at Lipiny]. Their friendship is evidenced by their extensive correspondence, which, however, has so far been published in limited excerpts only.