Dublin Castle (Bermingham Tower), Dublin Castle, Dublin 2, Co. Dublin

Beneath its eighteenth-century plasterwork and Gothic tracery lies a medieval core built around 1220, the sort of grim, defensive stonework you would expect from a fortress corner tower. Yet by the time you reach the first floor, the mood shifts entirely: a room of radial-patterned plaster ceilings, marble chimneypieces and delicately moulded cornices, more suited to a drawing room than a stronghold. The contrast is the point. Few structures in Dublin show so plainly how a building can carry two entirely different characters within the same walls, one grafted onto the other across five and a half centuries.

The tower forms the southwest corner of the medieval castle, and together with the Record Tower on the opposite side, gives some sense of how substantial that original fortress must have been. Its lower storey still shows the rough, uncoursed rubble limestone and battered base typical of thirteenth-century defensive building, thick walls built to withstand siege rather than admire. That practical origin was largely obscured in 1775-7, when the tower was rebuilt above ground-floor level, a change tentatively credited to the architect Thomas Penrose. The rebuilding introduced pointed-arch windows with hood-mouldings, cast-iron balconettes and rendered upper floors, making it an early Dublin example of Gothic Revival design, a style that borrowed medieval forms for decorative rather than defensive purposes. The result reads almost as commentary: a fortress reimagined in the architectural language of romance rather than warfare. Inside, the first-floor Bermingham Tower Room carries this furthest, with its Y-tracery fanlights, raised-and-fielded panel doors and quatrefoil ceiling panels, and it now functions as a hinge point in the plan, linking St Patrick's Hall, the Wedgwood Room and the Picture Gallery within the castle's State Apartments.

A metal plaque at the base of the tower, on its south side, sets out the building's history for anyone approaching from that direction, a useful marker given how much has changed above the original stonework. The perron staircase, a raised external stair leading up to the entrance, climbs from the east side behind a rubble stone wall, giving access to the ground floor. Looking up from outside, the shift in materials tells its own story: uncoursed rubble and limestone stringcourses at the base give way to painted render on the top two floors, a visible seam between the medieval fabric and its eighteenth-century remodelling.