military defence of southern Ireland. He based his defences upon walled towns, which Cromwell systematically took one after the other with his ample supply of siege artillery. The Irish and Royalist field armies did not hold any strategic line of defence and instead were demoralised by a constant stream of defeats and withdrawals. Only at the siege of Clonmel did Cromwell suffer significant casualties (although disease also took a very heavy toll on his men). His losses were made good by the defection of the Royalist garrison of Cork, who had been Parliamentarians up to 1648, back to the Parliament side. Cromwell returned to England in 1650, passing his command to Henry Ireton. In the north, the Parliamentarian/settler army met the Irish Ulster army at the battle of Scarrifholis and destroyed it. Ormonde was discredited and fled for France, to be replaced by Ulick Burke, Earl of Clanricarde. By 1651, the remaining Royalist/Irish forces were hemmed into an area west of the River Shannon, holding only the fortified cities of Limerick and Galway and an enclave in County Kerry, under Donagh MacCarthy, Viscount Muskerry. Ireton besieged Limerick while the northern Parliamentarian army under Charles Coote besieged Galway. Muskerry made an attempt to relieve Limerick, marching north from Kerry, and was routed by Roger Boyle at the battle of Knocknaclashy. Limerick and Galway were too well defended to be taken by storm, and were blockaded until hunger and disease forced them to surrender, Limerick in 1651, Galway in 1652. Waterford and Duncannon also surrendered in 1651. Guerrilla War While formal resistance ended, the harsh surrender terms resulted in a period of guerrilla warfare by bands of former soldiers, known as Tóraidhe or 'Tories.' These operated from rugged areas such as the Wicklow Mountains, looting supplies and attacking Parliamentary patrols, who responded with forced evictions and the destruction of crops. The result was widespread famine, aggravated by an outbreak of bubonic plague. The last organised Irish force surrendered in Cavan in April 1653 and given passage to France to either serve in the French army or with the English Royalist Court in exile. Those captured after this point were executed or transported to penal colonies in the West Indies. Ireland was plagued with small scale violence for the remainder of the 1650s, partly due to the 1652 Act for the Settlement of Ireland. This created a class of landless former farmers and