This 13th century hall house was likely built by Richard de St. Michael, Lord of Rheban, whose father had witnessed Strongbow’s grants in the late 12th century. Richard paid a hefty fine of £100 to King John in 1215 to secure his father’s lands, which included both Woodstock and the castle of Rheban. The positioning wasn’t accidental; the castle faced the river where a quay or harbour may have served the fortress, whilst nearby rectangular earthworks in the marshy ground to the southeast might be the remains of medieval fish ponds. Just 520 metres south, Richard also founded a religious house for the Crutched Friars, creating a small but significant medieval complex along this stretch of the Barrow.

The castle’s strategic importance made it a prize worth fighting for throughout its history. In 1315, Robert Bruce seized both Woodstock and Rheban during his Irish campaign, and a decade later Lysagh O’More took possession of both manors. The properties eventually passed as dowry lands to Thomas FitzGerald, seventh Earl of Kildare, around 1424 when he married Dorothy, daughter of Anthony O’More of Leix. This marriage brought not just the castles but the town of Athy itself under FitzGerald control, where they established court baron and court leet. The turbulent 1640s saw the castle change hands multiple times; the Marquis of Ormond took it from rebels in 1642, Owen Roe O’Neill surprised the garrison and put them to the sword in 1647, only for Lord Inchiquin to force its surrender shortly after.

What remains today is a substantial Anglo-Norman hall house that underwent significant modifications over the centuries. Originally built as a two storey structure with a first floor entrance, it was later enhanced with a square tower added to the south side in the 16th century, built to match the river facing front. The thick walls have survived remarkably well considering the battles they’ve witnessed, and the mullioned windows were noted for their elegant execution. The castle once boasted an elaborate fireplace adorned with carved figures in bas relief, including a 16th century carving of a bagpiper that was removed to Kilkea Castle. Archaeological earthworks in the surrounding fields hint at additional structures shown in a 1795 drawing, including a bawn wall and various buildings that formed part of this once formidable riverside fortress. The 1656 Down Survey map even depicts a small settlement clustered between Woodstock Castle and the Crutched Friars’ house, suggesting this was once a bustling medieval community along the Barrow.