Battle of Knocknanuss The Battle of Knocknanauss was fought in 1647 , during the Irish Confederate Wars , part of the Wars of the Three Kingdoms , between Confederate Ireland ’ s Munster army and an English Parliamentarian army under Murrough O ’ Brien . The battle resulted in a crushing defeat for the Irish Confederates . Background . In the summer of 1647 , Murrough O ’ Brien ( later created the Earl of Inchiquin ) , commander of the English Parliamentarian forces in Cork , ravaged and burned the Confederate territory in Munster . This caused severe food shortages and earned O ’ Brien the Irish nickname , " Murchadh an dTóiteán " ( Murrough the burner ) . In addition , Inchiquinn took the Rock of Cashel , which was garrisoned by Confederate troops but was also rich in emotive religious symbolism . In the sack of the castle , O ’ Brien ' s troops massacred the garrison and also all the clergy they found there . The Confederates ' Munster army was incapable of stopping O ’ Brien because of political infighting between officers who supported a deal with the English Royalists and those who rejected such a deal . Eventually , in reaction to the sack of Cashel and when near famine conditions were approaching as a result of O ’ Brien ’ s pillaging , the Confederate Supreme Council replaced Donagh MacCarthy , Viscount Muskerry , as commander of the Munster army with Viscount Taaffe and ordered him to bring O ’ Brien to battle . Taaffe was an English Catholic and not an experienced soldier . Moreover , although he had an excellent contingent of veteran troops under Alasdair MacColla , most of his men were similarly inexperienced . Furthermore , the Irish troops were demoralised by the internal factionalism in their ranks and most of them had little loyalty to Taafe . O ’ Brien , on the other hand , had been commanding his force since 1642 and was well tried in battle . His troops were a mixture of well trained Parliamentarian soldiers shipped from England and British settlers who had been driven from their homes in the Irish Rebellion of 1641 . The two armies met at Knocknanauss , near Mallow in County Cork in November 1647 . The battle . The battle that followed was essentially an uncoordinated rout of the Irish forces . Taafe positioned his men on either side of a hill , so that they could not see one another . The result was that one wing of the Confederate army had no idea of what the other wing was doing . MacColla ’ s men charged the Parliamentarians opposite them putting them to flight and killing a large number of them . Thinking the battle was over , they then took to looting the enemies baggage train . However , on the other wing , O ’ Brien ’ s cavalry had charged the raw Irish horsemen , causing them to run away . Despite Taafe ’ s desperate attempt to rally them , the Irish infantry followed suit , many of them being cut down by the pursuing roundheads . The pursuit continued for miles and not only resulted in heavy casualties among the Irish , but also in the loss of most of their equipment and supplies . MacColla and his men surrendered when they realised what had happened but were subsequently killed by their captors . Around 3 , 000 Confederates died at Knocknanauss , and up to 1 , 000 English Parliamentarians . The carnage did not stop after the fighting was finished . The next day a couple of hundred Irish soldiers were found sheltering in a nearby wood . These were promptly put to the sword . Outcome . When combined with the battle of Dungans Hill in County Meath , the defeat led to the collapse of the Confederate Catholic cause and forced them to make a deal with the English Royalists .