Query: Who was the principal of the Polish Literary Society that Frédéric became acquainted with?
Context: During his years in Paris he was to become acquainted with, among many others, Hector Berlioz, Franz Liszt, Ferdinand Hiller, Heinrich Heine, Eugène Delacroix, and Alfred de Vigny. Chopin was also acquainted with the poet Adam Mickiewicz, principal of the Polish Literary Society, some of whose verses he set as songs.