The keep was built for Henry II in 1172, but I learned that he never cam to see it. the Black Gate was named after Patrick Black ( sheriff ?) in 1247. Well worth a visit. In my day I used to train spot from the keep roof on a Saturday to see the Flying Scotsman and the Mallard ! And I only paid a tanner to go in !
A lot of people may not know that the battlements on the keep were added by John Dobson and you can see the line of his work on the outside..