Question: The Passacaglia for orchestra, Opus 1, is the first published composition of twentieth century Austrian composer Anton Webern, who was mentored by who?
Sentence (from "Anton Webern"): As an exponent of atonality and twelve-tone technique, Webern exerted influence on contemporaries Luigi Dallapiccola, Křenek, and even Schoenberg himself.
Relevant evidence: No