Question: what was the center of the byzantine empire
[{'answer': 'Constantinople', 'provenance': [{'wikipedia_id': '16972981', 'title': 'Byzantine Empire', 'start_paragraph_id': 1, 'start_character': 216, 'end_paragraph_id': 1, 'end_character': 230, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '16972981', 'title': 'Byzantine Empire', 'start_paragraph_id': 76, 'start_character': 0, 'end_paragraph_id': 76, 'end_character': 781, 'bleu_score': 0.983537688954433, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10210185672654968903}, 'section': 'Section::::History.:Macedonian dynasty and resurgence (867–1025).:Apex.\n'}]}]