Fresh foes met them on every side; and, after a bloody struggle, the men of Munster were conquered.

Callaghan, the king, and Prince Duncan, son of Kennedy, were brought captives to Dublin.

Then the royal prisoners were removed to Armagh, and their safe keeping entrusted to nine Danish earls, who had a strong military force at their orders to guard them.
"The news of this insidious act rapidly fanned the ardour of the Munster troops to be revenged for the imprisonment of their beloved king.
Kennedy, the Prince of Munster, father of Duncan, was appointed regent, with ample powers to govern the country in the king's absence.

The first step was to collect an army to cope with the Danes.

To assemble a sufficient body of troops on land was easy; but the great strength of the northern rovers lay in their swift-sailing ships.