The walls in question are hard to ignore: the dividing masonry between Nos. 2 and 3 rises to between six and seven metres, is ninety centimetres thick, and is built of roughly coursed rubble limestone. At a height of six metres on the north face there is a projecting corbel, and at four metres a moulding in dressed limestone, with a similar detail visible on the wall between Nos. 3 and 4. The local belief in a religious origin is understandable, given the scale and quality of the stonework, but the Urban Survey of Limerick, published in 1989 by Bradley and colleagues, concluded that these are more likely the walls of a substantial private house.

The confusion deepened considerably when nineteenth-century Ordnance Survey maps compounded the mistake. The 1840 OS map labels the site as "St Nicholas Abbey," and the 1870 edition compounds this as "St Nicholas's Abbey, (remains of)." Excavations carried out in 1994 by archaeologist Celie O'Rahilly, working under licence No. 94E072, clarified matters considerably. There was, in fact, no St Nicholas Abbey in Limerick. There was a medieval parish church dedicated to St Nicholas, but it stood further north, close to King John's Castle, and was demolished following the siege of 1692, after which the Corporation built the Widows Alms Houses on the site. What the walls on Nicholas Street actually represent, O'Rahilly's work confirmed, are the remains of two late medieval castellated town houses, meaning fortified urban residences with defensive features, that once fronted directly onto the street. Three cuttings were opened across Nos. 3, 5, and 6; all proved to have been cellared, and the third was filled with cut stone rubble, possibly material from the partial demolition of the medieval houses before 1930s buildings replaced them. Architectural fragments recovered during the work, along with an arched doorway noted in the northernmost wall, point to the quality of the original structures. The site was added to the Register of Historic Monuments on 17 June 1994.

The walls are on the west side of Nicholas Street, within the historically significant Englishtown area of Limerick city, the older of the city's two medieval islands. Visitors should be aware that substantial damage was done before proper protections were in place: the dividing wall between Nos. 4 and 5, which had survived multiple rebuilds, was demolished in 1992 under the Dangerous Buildings Act, and part of the northernmost wall containing the arched doorway was lost at the same time. What remains is incorporated into later development. The corbel and limestone moulding details visible on the surviving walls reward a careful look, offering a quiet reminder that behind the nineteenth-century mapmakers' confusion lies a story of prosperous medieval urban life rather than any ecclesiastical foundation.