Military history of Ireland
The Vikings pillaged monasteries on Ireland's west coast in 795, and then spread out to cover the rest of the coastline. The north and east of the island were most affected. During the first 40 years, the raids were conducted by small, mobile Viking groups. From 830 on, the groups consisted of large fleets of Viking ships. From 840, the Vikings began establishing permanent bases at the coasts. Dublin was the most significant settlement in the long term. The Irish became accustomed to the Viking presence and culture and in many cases became allies, with intermarriage common throughout Ireland. A major Irish battle involving Vikings was fought at the Battle of Clontarf in 1014, in which a large force of Vikings and their Irish allies were defeated by the gathered Irish forces of Brian Boru, then the High King of Ireland along with a small contingent of Viking defectors. After this date Viking activity was sporadic with various Kings and nobles attempting to extend their power base. In 1099, Magnus Barefoot, the King of Norway, and his Viking army had successfully campaigned alongside their Irish allies against opposing Irish warbands. On his return his force was ambushed and killed on the north coast of Ireland.
Vikings
The 200-year Viking influence on European history is filled with tales of plunder and colonisation, and the majority of these chronicles came from western witnesses and their descendants. Less common, though equally relevant, are the Viking chronicles that originated in the east, including the Nestor chronicles, Novgorod chronicles, Ibn Fadlan chronicles, Ibn Rusta chronicles, and brief mentions by Photius, patriarch of Constantinople, regarding their first attack on the Byzantine Empire. Other chroniclers of Viking history include Adam of Bremen, who wrote, in the fourth volume of his "Gesta Hammaburgensis Ecclesiae Pontificum", "[t]here is much gold here (in Zealand), accumulated by piracy. These pirates, which are called "wichingi" by their own people, and "Ascomanni" by our own people, pay tribute to the Danish king." In 991, the Battle of Maldon between Viking raiders and the inhabitants of Maldon in Essex was commemorated with a poem of the same name.