The guidebook tells us that Rockingham followed the standard Norman pattern which consisted of an outer bailey, courtyard, drawbridge and a curtain wall. Rockingham was a place for important historical events for example in 1096 king William II held a debate there. Source 13 tells us that the Domesday book says Rockinham was built in 1066, source 15 says William built the castle and source 1 says Rockingam was a typical Motte and bailey castle both source 13 and 15 support the guide book but the guide book does not tell us that Rockingham having 2 baileys was out of the ordinary we know it was from the diagrams in the Bayeux tapestry. But I think that the guide book is a reliable source of information on when Rockingham was first built.