Question: what does pax romana mean and why is it important
[{'answer': 'Roman Peace', 'provenance': [{'wikipedia_id': '44441', 'title': 'Pax Romana', 'start_paragraph_id': 1, 'start_character': 27, 'end_paragraph_id': 1, 'end_character': 38, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'a long period of relative peace and minimal expansion experienced by the Roman Empire'}, {'provenance': [{'wikipedia_id': '44441', 'title': 'Pax Romana', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 691, 'bleu_score': 0.5226254463829031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6136773566694053450}, 'section': 'Section::::Abstract.'}]}]