The map depicts it as a substantial L-shaped building, with what appears to be a curious U-shaped or half H-plan house attached to its southwestern corner. This addition, possibly dating from the 17th century, featured formal gardens stretching to the south; a rather grand arrangement for what was, by then, already considered ancient. The castle stood west of Cabbage Garden Lane, now known as Cathedral Lane, marking this corner of Dublin with its imposing presence.

This wasn’t just any old fortification; it was known as the Chancellor’s Manse, positioned strategically south of St Patrick’s Cathedral. An inquisition from 1546 provides a fascinating glimpse into its status, describing it as “a castle lying outside the precincts of the parish of St Kevin”. The building’s importance to the medieval church administration is evident from its prestigious title, though by the early 19th century, it had fallen into ruin. Contemporary accounts from this period suggest the structure still stood as a romantic, if crumbling, reminder of Dublin’s ecclesiastical power structures.

Today, nothing visible remains of the Old Castle above ground, its stones likely recycled into the expanding Georgian city or buried beneath centuries of urban development. The site represents one of those tantalising gaps in Dublin’s archaeological record; we know from historical documents and cartographic evidence exactly where it stood and something of its appearance, yet the physical structure has completely vanished. Its story survives only through maps like Rocque’s meticulous survey and scattered documentary references, leaving historians and archaeologists to piece together the life of this once significant building from fragments of the written record.