The modern Irish cities of Dublin, Limerick, and Waterford were founded around the year 800CE by Old Norse-speaking Vikings. These and other smaller Hiberno-Norse towns became important players in Gaelic Irish dynastic struggles of the ninth to eleventh centuries. Archaeology provides valuable information about the footprint of these towns, but their actual appearance from century to century is difficult to ascertain. Additional textual evidence comes from sources, which narrate the history of the Norse in Ireland for a patron.
The most famous of these sources is Cogad Gáedel re Gallaib, written about Brian Bóru for his great-grandson Muirchertach Ua Briain around 1100. Two others are Cathréim Cellacháin Caisil written for Cormac Mac Cárthaig around 1130, and the Cerball of Osraige saga written for the Mac Giolla Phádraig dynasty around 1030 and preserved in the Fragmentary Annals. These sources describe war with the Norse in the ninth and tenth century, as well as the 1014 Battle of Clontarf in Dublin within Cogad. Where the Viking settlements in these narratives have features such as walls and battlements, the description likely matches the Hiberno-Norse towns of the author’s awareness.
Dublin is described in Cogadh as two settlements: Dubhlinn (‘Dark-pool’) which became Dyflin in Old Norse, and Atha Cliath (‘Ford of Reed Hurdles’), which survives in modern Irish as Baile Átha Cliath. At one point the Norse town is described as ‘Dublin of Áth Cliath’, which suggests that, Dubhlinn may be the specific name for the Norse region, while Áth Cliath is the general settlement on the River Liffey. There is a town (baile) and a market (margad, a Norse loan word) where Brian sets up camp, as well as a fortress (dún).
This fortress is associated with Hiberno-Norse ruler Amlaibh, who submits to Brian and as part of their agreement gets back ‘his fortress’ (a dhún). The plain of Clontarf is visible from this fortress, as Amlaibh’s son Sitriuc watches the famous battle of 1014 from his personal quarters (grianan féin) on the battlement. There is also an open space or green (faci) to the west, in the area of modern Kilmainham.
Limerick is Luimneach in Middle Irish and transposed into Old Norse as Hlymrekr. Cogadh describes a fort and a ‘good town’ (degbali) there. It is unclear if there are also residences within the fort, as Brian’s men enter the fort and then slaughter the Norse ‘on the streets and in the houses’ (ar na srathaib 7 isna taigib). The Norse who escape regroup in the ‘western harbour of Limerick’ (iartharach Lumnig), the seaward side of the River Shannon.
A similar scene in Cellacháin sees the titular character’s forces go into Limerick, where the Norse cannot ‘close the gates’ (na doirsi na dunad) of the fort and are slaughtered ‘in the houses and in the towers’ (isna tignibh 7 isna toraibh). There are civilians present in Limerick, as the Norse give up ‘their wives and children [lit. dear sons] and households’ (mna 7 a maccaemha 7 a muintera) to Cellachán and his men.
Waterford is Port Láirge (‘Lárag’s Port’) in Middle Irish and Veðrafjörður (‘Wether [i.e. Ram] Fjord’) in Old Norse. In the saga of Cerball, the Norse are driven ‘into a small town with stone fortification around it’ (i mbaile beg 7 cloch dhaingean ime) and one of their leaders goes ‘up onto the rampart’ (ar an chaisiol). The Norse are besieged and a few of them escape, with wealthy spoils and ‘beautiful women left behind’ (ban caomh ro fagbhaid ann sin), indicating the presence of noncombatants.
Waterford also hosts civilians in Cellacháin, and may have been the designated place for the families of Norse across Munster. Cellachán’s men capture Limerick, Cork, and Cashel within the narrative and then go to Waterford. After winning a battle outside the town they go ‘where the women and families of the Norse were’ (a rabhatar mna 7 muinntera na Lochlannach) then burn the ‘town’ (baili). Cellachán’s forces then go onto the ‘green’ (faigthi) of Waterford, when a fleet of Norse ships arrives. The Norse already in Waterford close ‘the gates’ (doirsi) and attempt to defend themselves; nonetheless they are defeated once more by Cellachán and his men.
Norse towns in these three Middle Irish texts are described with nearby greens (faichi), a town (baile), and a fort (dún) or other enclosure that can be closed with a gate (doirse). In Dublin, the fort seems to have been separate from the living quarters of the town, although both Amlaibh and Sitriuc have a personal connection to the fort. Noncombatants reside within the gates in Limerick and Waterford. Little is said about the harbours, which must have been vital for these towns, nor the mechanisms by which they collected tribute and supplies from their hinterlands. These ninth and tenth century Viking towns of the Irish imagination give us a snapshot of the eleventh and twelfth century Hiberno-Norse reality they encountered, which is hidden from us today by centuries of development.
 Cogadh Gáedhel re Gallaibh: The War of the Gaedhil with the Gaill, or, The Invasions of Ireland by the Danes and Other Norsemen, ed. and trans. by J. H. Todd (London: Longmans, Green, Reader, and Dyer, 1867).
 Caithréim Cellacháin Caisil: The Victorious Career of Cellachan of Cashel, or, The Wars Between the Irishmen and the Norsemen in the Middle of the 10th Century, ed. and trans. by A. Bugge, Det Norske Historiske Kildeskriftfond (Christiana: J. Chr. Gundersens Bogtrykkeri, 1905).
 Fragmentary Annals of Ireland, ed. and trans. by J. N. Radner, (Dublin: Dublin Institute for Advanced Studies, 1978). Also available online through Corpus of Electronic Texts (CELT): <https://celt.ucc.ie/published/G100017/index.html>
 Cogadh ed. Todd, p. 35.
 Ibid., p. 113.
 Ibid., p. 119.
 Ibid., p. 191.
 Ibid., p. 151, 155.
 Ibid., p. 81.
 Ibid., p. 79.
 Ibid., p. 85.
 Cellacháin ed. Bugge, p. 66.
 Fragmentary Annals ed. Radner, p. 109.
 Ibid., p. 125.
 Cellacháin, p. 70-1.