Dublin Castle has been the centre of power in Ireland since the Normans built a fortification here in the early 13th century. The site was already significant before that — a Viking stronghold stood here, and traces of it are visible in the Undercroft below the modern courtyard. The city's name derives from Dubh Linn, the "Black Pool" of the River Poddle, which once ran through what is now the Castle Garden.
The Record Tower is the most visible remnant of the original Norman castle. The adjacent Chapel Royal, built in the early 19th century in Gothic Revival style, has fine plasterwork and carved oak galleries. The State Apartments in the south range were the residential and ceremonial heart of British viceregal administration — lavishly decorated and open for guided tours. The Great Courtyard is freely accessible; the State Apartments and Undercroft require a ticket.