Castiglioni was a profilic composer and highly influential writer and teacher (one of his pupils was Esa-Pekka Salonen). He graduated from the Milan Conservatory with diplomas for both piano performance and composition, and in the late 1950s and early '60s attended the Darmstadt summer courses that were a wellspring for post-war musical modernity. In the late '60s he taught for four years in the United States, and after returning to Italy taught in various posts there for the last 20 years of his life, including 17 at his alma mater in Milan.

The summers in Darmstadt were decisive for Castiglioni, who devoted much time to the study of Webern's music. The concision and transparent textures of Webern are also important elements in much of Castiglioni's own music, including the relatively late Cantus Planus, its two parts composed in 1990 and 1991 for the Ensemble Contrechamps in Geneva. These are settings of the mystical couplets of Angelus Silesius, whom Castiglioni compared with Webern in the union of simplicity and profundity.

Angelus Silesius was the pseudonym of the 17th-century Silesian poet-priest Johann Scheffler. Brought up a Lutheran and trained as a physician, Silesius joined the Roman Catholic Church in 1652, becoming a priest and a stridently anti-Protestant voice of the Counter Reformation. He published a collection of 205 hymns, some of which are still in use, and Cherubinischer Wanders-mann (The Cherubinic Wanderer), an extraordinary collection of many hundreds of rhymed couplets that combine the epigrammatic flavor of folk mottos with an almost pantheistic mysticism that has proved enduringly influential. (Jorge Luis Borges considered the line "Die Rose ist ohn' Warum; sie blühet, weil sie blühet" [The rose is without reason; she blooms because she blooms - set in No. 9 of the first part of Cantus Planus] to be the definition of poetry.)

Each part of Cantus Planus consists of 12 tiny songs. The title refers to plain song, of course, and Castiglioni employs many devices and techniques of medieval and renaissance music, including species counterpoint, organum, hocket, canon, and isorhythm. Textures vary dramatically, sometimes within a song as Castiglioni responds to the text.

Castiglioni's main pitch material is 12-tone, but not used dogmatically. Pedal tones and ostinatos abound, as well as all sorts of tonal references, such as the distant little folktune the second soprano sings in No. 3 of Part One. (The metrical relationships between the parts in that song - and many others - compare to Adès' temporal manipulations in his Piano Quintet.) Each piece is to be separated by a long pause, but Castiglioni also makes connections between them. Some are more theoretical than audible, but persistent rhetorical gestures give the work an expressive unity.

- John Henken is Director of Publications for the Los Angeles Philharmonic Association.