Question: who abandoned traditional harmony and created the twelve-tone system for composition
[{'answer': 'Arnold Schoenberg'}, {}, {'provenance': [{'wikipedia_id': '98764', 'title': 'Serialism', 'start_paragraph_id': 10, 'start_character': 0, 'end_paragraph_id': 10, 'end_character': 878, 'bleu_score': 0.8835357407016181, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13926120829028337088}, 'section': 'Section::::Basic definitions.:Twelve-tone serialism.\n'}]}, {'provenance': [{'wikipedia_id': '67025', 'title': 'Arnold Schoenberg', 'section': 'Section::::Abstract.', 'start_paragraph_id': 3, 'end_paragraph_id': 3, 'meta': {'evidence_span': ['In the 1920s, Schoenberg developed the twelve-tone technique, an influential compositional method of manipulating an ordered series of all twelve notes in the chromatic scale', 'Schoenberg was known early in his career for simultaneously extending the traditionally opposed German Romantic styles of Brahms and Wagner. Later, his name would come to personify innovations in atonality (although Schoenberg himself detested that term) that would become the most polemical feature of 20th-century art music.']}}]}]