Question: when did christianity become the roman empire official religion
[{'answer': 'in 380 AD', 'provenance': [{'wikipedia_id': '27928643', 'title': 'State church of the Roman Empire', 'start_paragraph_id': 1, 'start_character': 31, 'end_paragraph_id': 1, 'end_character': 40, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]