Question: who was the roman emperor when christ was born
[{'answer': 'Tiberius', 'provenance': [{'wikipedia_id': '30536', 'title': 'Tiberius', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 8, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]