The discovery came not from a dedicated excavation but from the routine groundwork that precedes construction, the kind of investigation that so often produces the most unexpected results. What emerged was a sequence of banks and ditches that once held back, or at least managed, the waters of the city's earliest urban edge.

Pre-development excavations at 3-15 Hammond Lane and 161-168 Church Street uncovered a series of earthen banks and associated ditches interpreted as river defences, a revetment being a structure built to retain or redirect water or earth along a riverbank. Radiocarbon dating of the primary fill in one of the ditches produced calibrated dates ranging from AD 1010 to 1160, placing the feature firmly in the late Hiberno-Norse period, when Dublin was consolidating itself as a significant trading settlement. Pottery recovered from the upper layers of both the bank and ditch pushed the use of the site into the 12th and 13th centuries. Between the banks, excavators identified several lines of stake-holes arranged to form rectangular boxes, suggesting a timber framework that would have reinforced the earthworks and helped stabilise the bank structure against the pressure of water and saturated ground. The findings were reported by A. Cryerhall in the 2006 volume of Excavations, covering fieldwork carried out in 2003.

There is nothing to see at ground level today; the site has long since been built over, and the finds themselves are the record. The value is in knowing that Church Street and Hammond Lane, busy and largely unremarkable to the passing eye, sit above evidence of organised civic engineering from a city that was still finding the shape of itself. Anyone interested in early medieval Dublin might use this as a prompt to look into the broader archaeology of the area, much of which survives only in excavation reports and museum collections rather than in visible remains.