While local tradition credits King John with its construction, the fortress was already well established by 1221, and records from 1185 mention a door-keeper, suggesting an even earlier origin. The location itself may have deeper roots still; some historians believe the Normans deliberately chose to build upon an earlier Viking strongpoint, layering centuries of conquest and control into the very foundations.

The medieval castle that once dominated this spot was an imposing rectangular keep with four attached towers, a formidable defensive structure that served as a symbol of Norman authority in southeast Ireland. For nearly three centuries, from 1311 to 1590, a succession of constables maintained order from within its walls, their names preserved in historical records. The castle’s military significance came to a dramatic end in October 1649 when Cromwell’s forces bombarded it during their Irish campaign. The garrison’s swift surrender led to the fall of Wexford itself, marking a pivotal moment in one of Ireland’s darkest chapters.

Today, visitors to the site will find no trace of the medieval fortress that once stood here. In the 1720s, the castle was converted into military barracks, and these Georgian buildings continue to occupy the location. While the stone towers and battlements have long since vanished, replaced by the more orderly architecture of the 18th century, the site remains a palimpsest of Irish history; Viking, Norman, Cromwellian and Georgian periods all converging on this single patch of ground in Wexford.