 From the 9th century , waves of Viking raiders plundered Irish monasteries and towns . These raids added to a pattern of raiding and endemic warfare that was already deep @-@ seated in Ireland . The Vikings also were involved in establishing most of the major coastal settlements in Ireland : Dublin , Limerick , Cork , Wexford , Waterford , and also Carlingford , Strangford , Annagassan , Arklow , Youghal , Lough Foyle and Lough Ree . 
 From the 9th century , waves of Viking raiders plundered Irish monasteries and towns . These raids added to a pattern of raiding and endemic warfare <a href='null_relcl' title='1'><mark>that</mark></a><a href='been_done' title='2'><mark></mark></a> was already deep @-@ seated in Ireland . The Vikings also <a href='uninflect' title='3'><mark>were</mark></a> involved in establishing most of the major coastal settlements in Ireland : Dublin , Limerick , Cork , Wexford , Waterford , and also Carlingford , Strangford , Annagassan , Arklow , Youghal , Lough Foyle and Lough Ree . 
From da 9th century , waves of Viking raiders plundered Irish monasteries and towns . dem raids added to a pattern of raiding and endemic warfare  been was already deep @-@ seated in Ireland . The falcons also was involved in establishing most of the major coastal settlements in Ireland : Dublin , Limerick , Cork , Wexford , Waterford , and also Carlingford , Strangford , Annagassan , Arklow , Youghal , Lough Foyle and Lough Ree .