"Pulcinella", as a subcategory of rearrangement of existing Baroque compositions, spawned a number of similar works, including Alfredo Casella's "Scarlattiana" (1927), Poulenc's "Suite Française", Ottorino Respighi's "Ancient Airs and Dances" and "Gli uccelli" , and Richard Strauss's "Dance Suite from Keyboard Pieces by François Couperin" and the related "Divertimento after Keyboard Pieces by Couperin", Op. 86 (1923 and 1943, respectively) . Starting around 1926 Béla Bartók's music shows a marked increase in neoclassical traits, and a year or two later acknowledged Stravinsky's "revolutionary" accomplishment in creating novel music by reviving old musical elements while at the same time naming his colleague Zoltán Kodály as another Hungarian adherent of neoclassicism . A German strain of neoclassicism was developed by Paul Hindemith, who produced chamber music, orchestral works, and operas in a heavily contrapuntal, chromatically inflected style, best exemplified by "Mathis der Maler". Roman Vlad contrasts the "classicism" of Stravinsky, which consists in the external forms and patterns of his works, with the "classicality" of Busoni, which represents an internal disposition and attitude of the artist towards works . Busoni wrote in a letter to Paul Bekker, "By 'Young Classicalism' I mean the mastery, the sifting and the turning to account of all the gains of previous experiments and their inclusion in strong and beautiful forms" . Neoclassicism found a welcome audience in Europe and America, as the school of Nadia Boulanger promulgated ideas about music based on her understanding of Stravinsky's music. Boulanger taught and influenced many notable composers, including Grażyna Bacewicz, Lennox Berkeley, Elliott Carter, Francis Chagrin, Aaron Copland, David Diamond, Irving Fine, Harold Shapero, Jean Françaix, Roy Harris, Igor Markevitch, Darius Milhaud, Astor Piazzolla, Walter Piston, Ned Rorem, and Virgil Thomson. In Spain, Manuel de Falla's neoclassical Concerto for Harpsichord, Flute, Oboe, Clarinet, Violin, and Cello of 1926 was perceived as an expression of "universalism" ("universalismo"), broadly linked to an international, modernist aesthetic .