The Black Gate was originally built (at a cost of GBP500) between 1247 and 1250 under the orders of Henry III, to strengthen the entrance to the castle. Once the castle ceased to have any strategic importance in the middle ages, the gatehouse was put to a number of uses. In the 17th century two new stories were added, and it was converted into tenements. Until recently it housed a bagpipe museum (now moved a few miles up the A1 to become the Morpeth Bagpipe Museum), and it is currently the headquarters of the Society of Antiquaries of Newcastle-upon-Tyne. Non-members may be allowed to visit by permission of the society's chief librarian.