In 1204, King John of England commissioned a stronghold to defend the city against potential Norman attacks. The Record Tower on the left, finished in 1228, is the oldest surviving building of the original Dublin Castle. It was used as a prison and is now the Garda or Police Museum. On the right is the Chapel Royal. The Gothic Revival structure by architect Francis Johnston was finished in 1814. In 1943, it became the Church of the Most Holy Trinity. Since 1922, the 11 acre castle property houses government offices. However, sections such as the State Apartments and two museums are available for public tours.