After Oliver Cromwell returned from Ireland in June 1650, he appointed Ludlow as lieutenant-general of horse and second-in-command to Henry Ireton in Parliament's campaign there. Here he spared neither health nor money in the public service. He landed in Ireland in January 1651 and was involved in the Siege of Limerick (1650–51). After Ireton's death on 26 November 1651, Ludlow held the chief command, and had practically completed the conquest of the island when he resigned his authority to Fleetwood in October 1652. Most of his campaigning in Ireland was against Irish guerrillas or "tories" and much of his operations consisted of hunting small bands and destroying foodstuff and crops. Ludlow is remembered for what he said of the Burren in County Clare during counter-guerilla operations there in 1651–52; "It is a country where there is not enough water to drown a man, wood enough to hang one, nor earth enough to bury him."