Fragments are all that remain of the great medieval fortress that once served as a symbol of Royal authority in Ireland and the centre of administration. Its construction began in 1204 when King John directed Meiler FitzHenry to make a castle "with good ditches and strong walls". Meiler chose a site on a ridge at the south-east corner of the city walls that was previously occupied by Henry II's "royal palace roofed with wattles" and possibly by a Hiberno-Norse forerunner. It was completed around 1228 and remained more or less intact until the 17th century when it was extensively rebuilt. The castle was an outstanding example of a "keepless" castle and has been compared to contemporary French castles such as Le Coudray-Salbart. Its east and south walls rose above the natural fosse provided by the River Poddle (now underground), whose waters also fed an artificial moat on its north and west sides.The castle had a comparatively uneventful history and only ever had to endure one siege, when Silken Thomas made an unsuccessful and rather disorganised attempt to capture it in 1534. For many centuries it was the official residence of the Lords Deputy and Lords Lieutenant of Ireland, the home of State councils, and sometimes Parliament and the Law Courts. Off Castle Street, Dublin 2. NGR: O 154339.