It is easy to walk past without a second thought, yet this unremarkable stretch of quayside sits directly over what cartographic evidence suggests was the original harbour of the Norse town, the very feature from which the city takes its name.

The Friends of Medieval Dublin Map, published in 1978, identifies this location as the site of the 'Dubh Linn', the black pool that gave Dublin its name in the Irish language. The pool itself was a tidal inlet where the River Poddle met the Liffey, sheltered enough to serve as a mooring point for Viking longships from at least the ninth century onwards. The name 'Dubh Linn' predates the Norse settlement, but it was the Scandinavian traders and raiders who made the harbour strategically significant, establishing a longphort, a fortified ship camp, in the vicinity during the 840s. Over the following centuries the pool was gradually enclosed, built over, and absorbed into the expanding medieval town, until it vanished entirely from the visible landscape.

There is nothing physically to see at the spot itself, which is part of what makes it worth knowing about. The location rewards a particular kind of attention, the sort that comes from carrying a map and a working awareness that the ground underfoot has been substantially altered over a thousand years of urban development. The 1978 Friends of Medieval Dublin Map, which remains a useful reference for anyone interested in the Viking and Norman phases of the city, places the pool in relation to surviving landmarks that can still be cross-referenced on foot. Dublin Castle's gardens occupy ground close to where the Poddle once surfaced, and the castle's lower levels have yielded archaeological traces of the early settlement. Visiting during quieter morning hours, when the area around the castle and the south city quays is less congested, makes it easier to orient yourself and picture the waterlogged, tidal geography that preceded the stone and concrete city now sitting on top of it.