Question: who wrote the magna carta and when was it written
[{'answer': '1215', 'provenance': [{'wikipedia_id': '20958', 'title': 'Magna Carta', 'start_paragraph_id': 2, 'start_character': 1362, 'end_paragraph_id': 2, 'end_character': 1366, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'John , King of England , his barons and Stephen Langton'}]