Battle of Knocknaclashy Boyle had inspired a mutiny among the English Royalist garrison in Cork, causing them to defect to the Parliamentarians. This had outflanked the defences of Irish Confederates and English Royalists, causing them to retreat behind the river Shannon into Connacht, where they held the fortified cities of Limerick and Galway. Henry Ireton went on to besiege Limerick. The only organised Irish forces remaining in south Munster were those of Donagh MacCarthy, Viscount Muskerry, who held out in the mountainous area of west Cork and county Kerry – which was his clan’s native territory. In July 1651, Muskerry set out from
Irish Civil War to defeat regular forces armed with artillery and armour. The only real conventional battle during the Free State offensive, the Battle of Killmallock, was fought when Free State troops advanced south from Limerick. Government victories in the major towns inaugurated a period of guerrilla warfare. After the fall of Cork, Liam Lynch ordered Anti-Treaty IRA units to disperse and form flying columns as they had when fighting the British. They held out in areas such as the western part of counties Cork and Kerry in the south, county Wexford in the east and counties Sligo and Mayo in the west.