The invasion of the Danes in 807 created a period of recurring battles throughout the country for the next 300 years. The main objective of the invaders was to rule the nation even if this meant wiping out the natives through torture and oppression as well as plundering and burning their property. Neither were the Danes averse to plundering, destroying and burning holy places or the slaughtering of monks. The Irish in turn set out to defend themselves and overcome the invaders. This met with incomplete success since even their defeat never meant that the Danes would not recover. Their foundation of the city of Limerick gave them a base in which to do so.
Calachan, the King of South Munster, became angry and distraught at the behaviour of the intruders. In response, he called all his chiefs to an assembly at his stronghold in Cashel. These included noted swordsmen like O’ Sullivan, O’ Riordan, O’ Landecan and Hugh Mac Cullenan. The king exhorted them to assemble their armies and launch a final attack on the Danes, who had gained absolute control of Limerick.
The king sent a message to the Danish commander named Auliff asking him to surrender Limerick and change their behaviour. The reply from the marauders was that their motto was: Battle before surrender. The Irish forces assembled and marched towards Limerick with O’ Sullivan being their general. They came face to face with the Danes at Singland and the fighting began with O’ Calachan motivating his men to keep up their spirits as the man to man combat began. The Chiefs O’ Callaghan, O’ Keeffe, O’ Sullivan and O’ Riordan fought Auliff, Magnus, Moran and Louchlin, respectively. Auliff was killed by O' Callaghan with one stroke of his sword breaking his opponent’s helmet and causing mortal injuries. Magnus was decapitated by O’Keeffe while Moran, son of the King of Denmark, also lost his head when O' Sullivan inflicted a blow behind his helmet and his shoulder. It took a long fierce fight before Louchlin was slain by O’ Riordan.
Following those losses, the Danes began to retreat into Limerick and were pursued by the Irish through the streets of the city until they were killed. Even houses were searched so that every Dane found met the same fate. When this battle ended, the king and his army marched back to Cashel. On their way, they encountered another army of Danes whom they engaged with every one of the five hundred foreigners meeting death.
While this overwhelming victory may seem the end of the Danes, more of them were arriving on the Irish coastline. The newcomers may have lessened their attacks on Christian sites but battles with the Irish continued with continuing violence. Malachy the Great engaged himself in controlling the Danes around Dublin while Brian Boru successfully did the same around Limerick. He avenged the killing by Ivor of his older brother Mahon and, on the defeat of Molloy who was slain at the battle of Ballagh Leachta, Brian became King of Munster.