makers were the Richmond Sixteen, who were conscientious objectors imprisoned there during the First World War. See also List of castles in England Notes References Notes Bibliography Further reading External links English Heritage's page on Richmond Castle Gatehouse record for Richmond Castle, containing a comprehensive bibliography http://news.bbc.co.uk/local/york/hi/people_and_places/religion_and_ethics/newsid_8342000/8342995.stm Castles in North Yorkshire Grade I listed buildings in North Yorkshire English Heritage sites in North Yorkshire Locations associated with Arthurian legend Ruins in North Yorkshire Scheduled monuments in North Yorkshire Richmond, North Yorkshire