The Souterrains of the Gaels in Ireland during the Viking Age

The Gaels in Ireland took refuge in souterrains or underground passageways during the Viking raids. They typically avoided armed resistance to fend off attacks on their settlements by Norse warbands.

  The Viking colonisation of Ireland in the ninth and tenth centuries brought a change to the defensive strategy used by the Gaels against their enemies. The Irish abandoned the building ring-forts after the Norse founded longphorts in the late ninth century. Ring-forts and cashels, or stone ring-forts, consisted of a settlement encircled by earthen banks. palisades and ditches. Archaeologists discovered forty-five thousand ringforts and cashels scattered across Ireland. The majority of ringforts dated to between 550 and 900 AD. They believe many more existed in the landscape in the Early Middle Ages.

The defences of the ring-forts proved too flimsy for attacks by professional Viking warriors. The Gaels resorted to hiding in the souterrains during raids by the Vikings. The underground chambers were just as successful in sheltering villagers from the Norse pirates as they were against warring Gaelic tribes in the eighth century. The Celts along the Atlantic coast of Britain, Ireland and Europe began building souterrains beneath their settlements in the Late Iron Age. The underground chambers served as storage areas for harvests, shelter for their livestock and a place of refuge during times of danger. Most of the Celtic territories dispense with souterrains in the third century AD. The underground passageways were prone to flooding, collapsed roofs and other similar disasters. Scholars concluded the Gaels built most of the souterrains in Ireland between 500 and 1200 AD. The 3,500 souterrains that survived in the landscape were typically part of the ring-forts. Some Irish communities reinforced the underground passageways constructed by their ancestors in the first and second centuries AD. The Gaels referred to the souterrains as uaimh meaning “cave.” Ordinance maps in Ireland still allude to the ancient passageways as “caves.” Souterrains were prevalent in southern and western Ireland. The Gaelic settlements feared raids by the Norse warriors at the Viking towns of Dublin, Cork, Limerick, Wexford and Waterford. The Vikings also terrorised the inhabitants of forts and villages near the loughs and adjacent islands. There were numerous accounts of Norse leaders raiding the Gaelic settlements around Lough Ree, Carlingford Lough and Strangford Lough. The Annals of Inisfallen claimed the Hiberno-Norse kings of Dublin, Bárid mac Ímair and Oistín mac Amlaíb, plundered the souterrains of the Gaels during a raid in north Kerry in 873. The fear of being captured and sold as slaves in the Viking towns prompted the Irish to pay high prices for the construction of souterrains in the Early Middle Ages. The owners paid an exorbitant cost of two cows to an uaimhreacht, or professional builder of the souterrains. The majority of souterrains in Ireland were beneath ring-forts and ecclesiastical buildings. The builders lined the walls and roof of the tunnels with stones and wood. The low ceilings and cramped conditions of the tunnels made entering and attacking the occupants extremely difficult. The doorway to a souterrain could be defended against marauders. The shapes and sizes of the souterrains varied according to the region. A beehive cavern recently discovered by a farmer in the Boyne Valley was a rarity in the area. The souterrains of the Boyne Valley normally resembled the ancient passage tombs of Knowth and Newgrange. A souterrain built at Tateetra near Dundalk in County Louth in the second century AD was the only defence against the Vikings at Woodstown. The Norse abandoned Woodstown in the early tenth century, The Annals of Ireland recounted Ottir the Black founded another naval base at Waterford in 914. The drystone walls of the souterrain at Tateetra formed a U shaped passageway with two doors. The crosses carved on two stones were talismans against the forces of evil. The drop-hole in the souterrain was "a defensive feature that would have made access difficult for intruders as they would have had to climb up or down to the next section of the souterrain, leaving themselves open to attack (Avril Hayes - Archaeological investigation of a souterrain at Tateetra). The souterrains of Ireland fulfilled a crucial role in protecting the Gaelic population against raids by Vikings. The underground passageways provided a means for the Irish to avoid capture and being sold into slavery by the Norse in the Viking towns.  

The early Viking history of Ireland is discussed in:

Olaf the White and Ivar the Boneless - The Viking Kings of Dublin: https://www.amazon.com/dp/B0916GJ3B2

And

Vikings in Ireland (870 - 914): https://www.amazon.com/dp/B096KVNBZK   References Drogheda Independent - Farmer unearths ancient souterrain: https://www.independent.ie/regionals/droghedaindependent/news/farmer-unearths-ancient-souterrain-27106743.html North Stoke - article by Thelma: https://northstoke.blogspot.com/2010/04/plundering-of-megalithic-tombs-by.html RIA - EARLY MEDIEVAL IRELAND AD 400–1100 by Aidan O’Sullivan, Finbar McCormick, Thomas R. Kerr and Lorcan Harney: https://www.ria.ie/sites/default/files/chapter_3_1.pdf When-What-How - Ringforts: http://what-when-how.com/medieval-ireland/ringforts-medieval-ireland/ Wikipedia - Souterrain: https://en.wikipedia.org/wiki/Souterrain TII - Archaeological investigation of a souterrain at Tateetra, Dundalk, County Louth by Avril Hayes:
 

https://www.tii.ie/technical-services/archaeology/publications/archaeologymonographseries/Mon-3-Ch-6-Hayes.pdf