Question: when did ad start being used in dates
[{'answer': '525', 'provenance': [{'wikipedia_id': '1400', 'title': 'Anno Domini', 'start_paragraph_id': 2, 'start_character': 343, 'end_paragraph_id': 2, 'end_character': 346, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1400', 'title': 'Anno Domini', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 425, 'bleu_score': 0.9748377259086851, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16949051503458163793}, 'section': 'Section::::Abstract.'}]}]