The Passacaglia for orchestra, Opus 1, is the first published composition of twentieth century Austrian composer Anton Webern, who was mentored by who?
Arnold Schoenberg
Title: Passacaglia for orchestra (Webern)
Passage: The Passacaglia for orchestra, Opus 1, is the first published composition of twentieth century Austrian composer Anton Webern.  It is based on the 17th century musical form, the passacaglia.
Title: Intermezzo in D minor (Bruckner)
Passage: The Intermezzo in D minor (WAB 113) is an 1879 composition by the Austrian composer Anton Bruckner.  Although it was intended to replace a movement of the String Quintet, that piece was instead performed in its original form; the Intermezzo was not publicly premiered until after the composer's death.
Title: Anton Webern
Passage: Anton Friedrich Wilhelm (von) Webern (] ; 3 December 188315 September 1945) was an Austrian composer and conductor.  Along with his mentor Arnold Schoenberg and his colleague Alban Berg, Webern was at the core among those within and more peripheral to the circle of the Second Viennese School, including Ernst Krenek and Theodor W. Adorno.  As an exponent of atonality and twelve-tone technique, Webern exerted influence on contemporaries Luigi Dallapiccola, Křenek, and even Schoenberg himself.  As a tutor, Webern guided and variously influenced Arnold Elston, Frederick Dorian (Friederich Deutsch), Matty Niël, Fré Focke, Karl Amadeus Hartmann, Philipp Herschkowitz, René Leibowitz, Humphrey Searle, Leopold Spinner, and Stefan Wolpe.
Anton Webern Passacaglia for orchestra (Webern)