The construction of the castle in Dublin began in 1204 at the request of King John. For strategic reasons, the confluence of the rivers Liffey and Poddle was chosen as the location of this defensive fortress. Since its completion, the fortress was rebuilt and renovated several times. It also served a variety of functions including a court, treasury and even a prison. Today the castle hosts a museum, however, its most representative interiors are also used during ceremonial occasions. The massive stone Record Tower is a characteristic feature of this complex of royal buildings.