Question: what served as centers of learning in early medieval europe
[{'answer': 'monasteries', 'provenance': [{'wikipedia_id': '532476', 'title': 'Early Middle Ages', 'start_paragraph_id': 38, 'start_character': 820, 'end_paragraph_id': 38, 'end_character': 831, 'bleu_score': 1.0, 'section': 'Section::::History.:Birth of the Latin West.:700–850.\n'}]}, {'answer': 'cathedrals', 'provenance': [{'wikipedia_id': '532476', 'title': 'Early Middle Ages', 'start_paragraph_id': 76, 'start_character': 74, 'end_paragraph_id': 76, 'end_character': 84, 'bleu_score': 1.0, 'section': 'Section::::Transmission of learning.\n'}]}, {'provenance': [{'wikipedia_id': '532476', 'title': 'Early Middle Ages', 'start_paragraph_id': 76, 'start_character': 0, 'end_paragraph_id': 76, 'end_character': 924, 'bleu_score': 0.9855586187885531, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9727739293849440510}, 'section': 'Section::::Transmission of learning.\n'}]}]