Jordan ' s Castle Jordan ' s Castle ( Ulster Scots : " Joardan ' s Kessel " ) is a castle situated in Ardglass , County Down , Northern Ireland . The tower house known as Jordan ' s Castle is a State Care Historic Monument sited in the townland of Ardglass , in Down District Council area , at grid ref : J5601 3713 . It stands close to the junction of Kildare and Quay Streets in Ardglass and commands the harbour . Features . It is a rectangular Tower house four storeys high , i . e . four superimposed single chambers each about 20 ft by 13 ft . On the north face are two rectangular projections , one containing a stone spiral staircase , the other an inner closet at each level , with those on the lower stages having outlets to the ground . Architecturally there is little evidence to give a definitive date for the castle . The masonry is blue stone rubble with a little freestone in quoins and window jambs . Some of the window details suggest 15th century , but have had so much reconstruction that dating is difficult . The ground floor chamber is unfloored and the irregular surface of the outcropping rock can be seen . It therefore may have been a storehouse . The main room is apparently on the first floor , which contains its original stone floor supported on a pointed barrel vault . The floors on the second and third storeys are at the original levels but of modern construction , with the beams going at right angles to the original direction . The concrete roof is also an addition . The wall tops retain their stone - flagged rampart walls and archery turrets . The turret to the north - west contains a dovecote , the nest - holes of which are contemporary with the main structure . The entrance is at the bottom of the north - west tower and leads to a spiral stairway to roof level . It is protected by a machicolation at that level . The projecting towers are connected by a high - level arch which also functions as a machicolation . The " Dublin Penny Journal " of 30 March 1833 describes Jordan ' s Castle as follows : History . Its early history is somewhat obscure . The earliest authentic reference is to a defence of the castle by Simon Jordan against the O ' Neills for three years , until relieved by Lord Deputy Mountjoy in 1601 . The 18th century historian , Harris , says that " it is most probable that Jordan ' s Castle was erected by one of the family , whose arms ( a cross and three horseshoes ) are fixed in a stone near the top " . In 1911 the Belfast antiquarian , Francis Joseph Bigger , bought the castle and restored it , using it to display his extensive collection of antiquities and making it freely accessible to everyone to bring local people ' into touch with the Irish past , and give them some conception of the historic background of their life ' . It was also extensively used for get - togethers of the wide circle of Irish Cultural revival artists and writers to whom Bigger was friend and patron . Following suggestions by Alice Stopford Green and the archivist Henry Egan Kenny , Bigger renamed the tower ' Castle Séan ' in honour of the two years when Shane O ' Neill controlled Ardglass , and they believed , re - fortified the tower following his defeat of the MacDonnells at Glentaisie in 1565 . When he died in 1926 , the castle was presented by his executor , Dr Joseph Bigger , to the state on condition that , with its contents , it should be preserved as an Ancient Monument . The contents have since been dispersed among the Ulster Museums general collections and the tower is no longer open to the public . Ardglass had at least six castles and remains of four of them can still be seen : Ardglass Castle , Cowd Castle , Margaret ' s Castle and Jordan ' s Castle .