Early Viking raids followed a similar pattern: their preferred victims were monasteries along the coast, places where two or three ships full of raiders were enough to carry off all the valuables and get away before local fighting men arrived.
Ireland's rich deposits of gold, silver, and copper have been mined since ancient times. Precious and semi-precious stones were also found on the island—emeralds, sapphires, amethysts, topaz, freshwater pearls, and "Kerry diamonds." And the Irish have a long tradition, dating at least to 2000 B.C, of producing metalwork of very high quality.
These native materials and skills combined with religious devotion to make the monasteries and convents of Ireland the richest in the British Isles and, as a result, the favorite targets of Viking raiders.
A chronicler in Munster bewailed the "immense floods and countless sea-vomitings of ships and boats and fleets so that there was not a harbor nor a land port nor a dun nor a fortress nor a fastness in all Munster without floods of Danes and pirates." The chronicler went on to report how the Vikings "ravaged [Munster's] chieftainries and her privileged churches and her sanctuaries, and they rent her shrines and her reliquaries and her books."
Archaeologists have discovered many sublime examples of Irish metalwork, stripped from holy places, in Viking graves throughout Scandinavia. How many other comparable works were melted down or lost?
Books were the sole Irish treasure that the Vikings did not prize. Once a book's gold or silver covers had been pried off, the Vikings had no further interest in it. They tossed books into fires, trampled them under foot, or dumped them in the sea or a nearby lake, causing Irish monks to lament the "drowning" of their precious manuscripts.
As the pillage, destruction, and slaughter spread across the country, some Irish monks gathered up their books and fled to the Continent. Many joined monastic communities in France, Germany, Belgium, or the Netherlands, or offered their services as teachers at the schools founded 20 or 30 years earlier by Charlemagne. Other monks chose the missionary life, carrying Christianity to remote corners of Austria and Switzerland. Irish monks had always been wanderers, but this exodus from Ireland was different.
There was a genuine sense among the monks of Ireland that their civilization was on the edge of extinction. If Irish sanctity and scholarship and artistry were to survive, they believed, it would have to be in foreign lands.