 Complete the following phrase:  During the Wars of the Roses, castles were infrequently attacked and conflict was generally based around combat in the field. Alnwick was one of three castles held by Lancastrian forces in 1461 and 1462, and it was there that the only practical defence of a private castle was made according to military historian D. J. Cathcart King. It was held against King Edward IV until its surrender in mid-September 1461 after the 