Question: who brought the idea of castles to england
[{'answer': 'Norman invaders', 'provenance': [{'wikipedia_id': '49557', 'title': 'Castle', 'start_paragraph_id': 10, 'start_character': 268, 'end_paragraph_id': 10, 'end_character': 283, 'bleu_score': 1.0, 'section': 'Section::::Definition.:Defining characteristics.\n'}]}, {'provenance': [{'wikipedia_id': '49557', 'title': 'Castle', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 488, 'bleu_score': 0.9513372234174611, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16858225323125029378}, 'section': 'Section::::Definition.:Etymology.\n'}]}, {'provenance': [{'wikipedia_id': '49557', 'title': 'Castle', 'start_paragraph_id': 10, 'start_character': 0, 'end_paragraph_id': 10, 'end_character': 612, 'bleu_score': 0.9796927878356411, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16858225323125029378}, 'section': 'Section::::Definition.:Defining characteristics.\n'}]}, {'provenance': [{'wikipedia_id': '49557', 'title': 'Castle', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16858225323125029378}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '142937', 'title': 'Castles in Great Britain and Ireland', 'section': 'Section::::Norman Invasion.:Anglo-Saxon fortifications.\n', 'start_paragraph_id': 7, 'end_paragraph_id': 7, 'meta': {'evidence_span': ['The English word "castle" derives from the Latin word "castellum" and is used to refer to the private fortified residence of a lord or noble. The presence of castles in Britain and Ireland dates primarily from the Norman invasion of 1066. Before the arrival of the Normans the Anglo-Saxons had built burhs, fortified structures with their origins in 9th-century Wessex.', 'There were, however, a small number of castles which were built in England during the 1050s, probably by Norman knights in the service of Edward the Confessor']}}]}, {'provenance': [{'wikipedia_id': '49557', 'title': 'Castle', 'section': 'Section::::Definition.:Defining characteristics.\n', 'start_paragraph_id': 10, 'end_paragraph_id': 10, 'meta': {'evidence_span': ['As William the Conqueror advanced through England, he fortified key positions to secure the land he had taken. Between 1066 and 1087, he established 36\xa0castles such as Warwick Castle, which he used to guard against rebellion in the English Midlands.', "astles were established by Norman invaders of England for both defensive purposes and to pacify the country's inhabitants.", "Castles were established by Norman invaders of England for both defensive purposes and to pacify the country's inhabitants."]}}]}]