This fortification appears on Thomas Sherrard’s detailed 1784 map of Athlone, where it’s clearly marked at the corner of what was then called St. George’s Lane. The map itself, preserved in the Representative Church Body Library as Manuscript 151, provides one of the few visual records of the castle’s original location and its relationship to the surrounding streetscape.

The castle’s alternative name, recorded by historian Harman Murtagh in 1994, hints at a connection to a family or individual named Cox, though the specifics of this association remain somewhat unclear. What we do know is that by the late 18th century, when Sherrard was documenting Athlone’s urban layout, the castle was significant enough to merit inclusion on his map, suggesting it was either still standing or its ruins were substantial enough to serve as a landmark.

The transformation of St. George’s Lane into Excise Street reflects the changing nature of Athlone itself; from a medieval town dominated by defensive structures to a more modern settlement focused on commerce and administration. Today, visitors to Excise Street might walk past the site without realising they’re treading near what was once a notable fortification, a reminder of how urban development can quietly erase centuries of history whilst leaving tantalising traces in old maps and documents.