Randal MacDonnell, Marquess of Antrim, raised an Irish Brigade, containing three regiments of foot, one of which was O'Cahan's. Colkitto's son Alastair McColla was appointed to command the Brigade but his objective of regaining family lands in South-West Scotland would ultimately clash with those of the Royalist leader, James Graham. Montrose fought for the Covenanters in the Bishops Wars; unlike England, Covenanters and Scottish Royalists both agreed monarchy itself was divinely ordered but differed on who held primacy in religious affairs. This meant many Scots like Montrose fought on both sides at various times; both the Second and Third English Civil Wars were fought by the Covenanter governments to restore first Charles I, then his son back on the English throne. In June 1644, O'Cahan's Regiment was shipped to Scotland with the other parts of the Brigade. MacColla and O'Cahan In 1641, as McColla raised his army in Ulster, on behalf of Randal MacDonnell (Earl of Antrim), a strong Royalist sympathiser, the Irish Rebellion of 1641 erupted. Catholics turned on Protestant settlers who were pouring into the country by the thousand under a much despised plantation programme. McColla, and a cousin by marriage, Manus O'Cahan, were thrown together in a joint Catholic-Protestant Scots-Irish peace keeping force. Finding themselves despised by the Protestants in the force, the Scot and the Irishman rebelled and went on a guerrilla warfare rampage throughout Northern Ireland. In the course of the conflict they developed a new battle technique known as the 'Irish Charge', which involved discarding heavy weapons such as pikes and muskets to rush the enemy to kill them at close quarter with dirks, daggers and swords or even with unarmed combat tactics. It proved to be highly effective, especially against musketeers who needed time to reload powder and shot between volleys. They perfected the art of running directly at cavalry to cut the horses in the bellies and fetlocks as they ran underneath them. This forced the agonised horses to throw their riders. McColla made himself unpopular in Ireland by changing sides, to serve the Protestants, and then changing sides again to serve Antrim and the Irish Catholic Confederation of which Antrim was a leader. As the Scottish Covenant forces declared military support for the English Parliament in late 1643, Antrim hit on a plan to send Catholic troops to Scotland. The aim was for them to cause as much destruction as possible,