In 1011, High King Brian Boru and the second most important king in Ireland, Malachy II of Meath, sailed up the Shannon and stayed a while at the ancient Abbey .
Ireland - Ireland - The Norse invasions and their aftermath: The first appearance of the Norsemen on the Irish coast is recorded in 795. Thereafter the Norsemen made frequent plundering raids, sometimes far inland. In 838 they seized and fortified two ports, Annagassan and Dublin, and in the 840s they undertook a series of large-scale invasions in the north of the country. These invaders were driven out by Aed Finnliath, high king from 862 to 879, but meanwhile the Norse rulers of Dublin were reaching the zenith of their power. They took Waterford in 914 and Limerick in 920. Gradually, without quite abandoning piracy, the Vikings became traders in close