The Northumbrian coast is castle after castle. Here are two with Shakespearian associations. Dunstanbrugh belonged to John of Gaunt and Warkworth to the Percys. Dunstanbrugh. That's an ace surfing beach, by the way. Warkworth. The keep went up in 1400- in the lifetime (just) of the famous Harry Hotspur- and is more residential than defensive.